Cache NUMBA kernels between CI runs

.github/workflows/ci.yaml

@@ -1,12 +1,15 @@
 name: QuartiCal CI Workflow
 
 # Specific github action events that you can lookup in their API
-on: 
+on:
   push:
     tags:
       - 'v*'
   pull_request:
 
+env:
+  NUMBA_CACHE_DIR: /tmp/numba-cache
+
 jobs:
   test:
     runs-on: ${{ matrix.os }}
@@ -34,12 +37,26 @@ jobs:
       - name: Upgrade pip and setuptools
         run: python -m pip install -U pip setuptools
 
+      - name: Construct Numba Kernel Cache Key and Directory
+        id: numba-cache-key
+        run: |
+          mkdir -p $NUMBA_CACHE_DIR
+          echo "date=$(/bin/date -u "+%Y%m%d")" >> $GITHUB_OUTPUT
+        shell: bash
+
+      - name: Cache Numba Kernels
+        uses: actions/cache@v3
+        with:
+          key: numba-cache-${{ steps.numba-cache-key.outputs.date }}
+          restore-keys: numba-cache-
+          path: $NUMBA_CACHE_DIR
+
       - name: List the measures directory
         run: curl ftp://ftp.astron.nl/outgoing/Measures/ > measures_dir.txt
 
       - name: Load cached CASA Measures Data
         id: load-cached-casa-measures
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           key: casa-measures-${{ hashFiles('measures_dir.txt')}}
           path: |