fix: update github ci workflows for new version

Summary:
- Add the latest elixir and otp version to the testing matrix. We've
  been running them at BatteriesIncluded for a while on the latest
  versions.
- Remove the restore keys field for plts. This causes us to re-generate
  new typespecs on new elixir versions (new otp versions as well but
  they don't seem to change the plts as much)

Test Plan:
- Green CI

.github/workflows/ci.yaml

@@ -52,8 +52,6 @@ jobs:
         with:
           key: |
             ${{ runner.os }}-${{ steps.beam.outputs.elixir-version }}-${{ steps.beam.outputs.otp-version }}-plt
-          restore-keys: |
-            ${{ runner.os }}-${{ steps.beam.outputs.elixir-version }}-${{ steps.beam.outputs.otp-version }}-plt
           path: |
             priv/plts
 

.github/workflows/elixir_matrix.yaml

@@ -13,14 +13,17 @@ jobs:
       fail-fast: false
       matrix:
         # See https://hexdocs.pm/elixir/1.13/compatibility-and-deprecations.html#compatibility-between-elixir-and-erlang-otp
-        otp: ["23.x", "24.x", "25.x", "26.x"]
-        elixir: ["1.14.x", "1.15.x", "1.16.x"]
+        otp: ["23.x", "26.x", "27.x"]
+        elixir: ["1.14.x", "1.17.x", "1.18.x"]
         exclude:
           # OTP 23
           - elixir: "1.15.x"
             otp: "23.x"
           - elixir: "1.16.x"
             otp: "23.x"
+          # OTP 26
+          - elixir: "1.18.x"
+            otp: "26.x"
 
     steps:
       - uses: actions/checkout@v4.1.7