ci: 👷 simplify the CI build process (#171)

Doesn't really need a review, this is only meant to help simplify the CI
auto-build process.

.github/workflows/build.yaml

@@ -0,0 +1,43 @@
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+on:
+  push:
+    branches: main
+  pull_request:
+    branches: main
+  release:
+    types: [published]
+
+name: Build package
+
+permissions: read-all
+
+jobs:
+  style:
+    uses: ./.github/workflows/reusable-style.yaml
+    permissions:
+      contents: write
+    secrets:
+      github-token: ${{ secrets.GITHUB_TOKEN }}
+
+  document:
+    uses: ./.github/workflows/reusable-document.yaml
+    needs: style
+    permissions:
+      contents: write
+    secrets:
+      github-token: ${{ secrets.GITHUB_TOKEN }}
+
+  cran-check:
+    uses: ./.github/workflows/reusable-cran-check.yaml
+    needs: document
+    secrets:
+      github-token: ${{ secrets.GITHUB_TOKEN }}
+
+  pkgdown:
+    uses: ./.github/workflows/reusable-pkgdown.yaml
+    needs: cran-check
+    permissions:
+      contents: write
+    secrets:
+      github-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/reusable-cran-check.yaml

@@ -0,0 +1,52 @@
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+on:
+  workflow_call:
+    secrets:
+      github-token:
+        required: true
+
+name: Run R CMD checks and tests
+
+jobs:
+  R-CMD-check:
+    runs-on: ${{ matrix.config.os }}
+
+    name: ${{ matrix.config.os }} (${{ matrix.config.r }})
+
+    strategy:
+      fail-fast: false
+      matrix:
+        config:
+          - {os: macos-latest,   r: 'release'}
+          - {os: windows-latest, r: 'release'}
+          - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
+          - {os: ubuntu-latest,   r: 'release'}
+          - {os: ubuntu-latest,   r: 'oldrel-1'}
+
+    env:
+      GITHUB_PAT: ${{ secrets.github-token }}
+      R_KEEP_PKG_SOURCE: yes
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: r-lib/actions/setup-pandoc@v2
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          r-version: ${{ matrix.config.r }}
+          http-user-agent: ${{ matrix.config.http-user-agent }}
+          use-public-rspm: true
+
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::rcmdcheck
+          needs: |
+            check
+            tests
+
+      - uses: r-lib/actions/check-r-package@v2
+        with:
+          upload-snapshots: true
+          build_args: 'c("--no-manual","--compact-vignettes=gs+qpdf")'

.github/workflows/reusable-document.yaml

@@ -0,0 +1,44 @@
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+on:
+  workflow_call:
+    secrets:
+      github-token:
+        required: true
+
+name: Run roxygen2 to build function documentation
+
+jobs:
+  document:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.github-token }}
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Setup R
+        uses: r-lib/actions/setup-r@v2
+        with:
+          use-public-rspm: true
+
+      - name: Install dependencies
+        uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::roxygen2
+          needs: roxygen2
+
+      - name: Document
+        run: roxygen2::roxygenise()
+        shell: Rscript {0}
+
+      - name: Commit and push changes
+        run: |
+          git config --local user.name "$GITHUB_ACTOR"
+          git config --local user.email "$GITHUB_ACTOR@users.noreply.github.com"
+          git add man/\* NAMESPACE DESCRIPTION
+          git commit -m "Update documentation" || echo "No changes to commit"
+          git pull --ff-only
+          git push origin

.github/workflows/pkgdown.yaml → .github/workflows/reusable-pkgdown.yaml

@@ -1,9 +1,12 @@
-name: Build website
-
 # Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
 # Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
 on:
   workflow_call:
+    secrets:
+      github-token:
+        required: true
+
+name: Build the pkgdown website
 
 jobs:
   pkgdown:
@@ -12,9 +15,7 @@ jobs:
     concurrency:
       group: pkgdown-${{ github.event_name != 'pull_request' || github.run_id }}
     env:
-      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
-    permissions:
-      contents: write
+      GITHUB_PAT: ${{ secrets.github-token }}
     steps:
       - uses: actions/checkout@v4