CI housekeeping (#104)

List of changes:
- add Elixir 1.17 / Erlang OTP 27 to CI
- bump github actions

.github/workflows/ci.yml

@@ -16,21 +16,21 @@ jobs:
       matrix:
         include:
           - pair:
-              elixir: "1.11.4"
-              otp: "21.3.8.17"
+              elixir: 1.11.3
+              otp: 21.3
           - pair:
-              elixir: "1.15.4"
-              otp: "26.0.2"
+              elixir: 1.17.2
+              otp: 27.0
             lint: lint
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - uses: erlef/setup-beam@v1
         with:
           otp-version: ${{matrix.pair.otp}}
           elixir-version: ${{matrix.pair.elixir}}
 
-      - uses: actions/cache@v3
+      - uses: actions/cache@v4
         with:
           path: |
             deps