Update CI Ruby versions (#90)

Author: alexgenco

.github/workflows/tests.yml

@@ -12,7 +12,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest]
-        ruby: [2.6, 2.7, 3.0, 3.1, head]
+        ruby: [2.7, 3.0, 3.1, 3.2, head]
     runs-on: ${{ matrix.os }}
     if: "!contains(github.event.head_commit.message, '[skip ci]')"
     steps:
@@ -38,7 +38,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [2.6, 2.7, 3.0, 3.1]
+        ruby: [2.7, 3.0, 3.1, 3.2]
     runs-on: windows-latest
     if: "!contains(github.event.head_commit.message, '[skip ci]')"
     steps: