[GitHub Actions] Test on swift 5.1, 5.2, 5.3

.github/workflows/swiftpm.yml

@@ -19,7 +19,7 @@ jobs:
   Xcode:
     strategy:
       matrix:
-        xcode_version: ['11.4.1']
+        xcode_version: ['11.3.1', '11.7', '12']
     runs-on: macOS-10.15
     env:
       DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode_version }}.app
@@ -31,10 +31,9 @@ jobs:
   Linux:
     strategy:
       matrix:
-        tag: ['4.2', '5.0', '5.1']
+        tag: ['5.1', '5.2', '5.3']
     runs-on: ubuntu-latest
-    container:
-      image: norionomura/swift:${{ matrix.tag }}
+    container: norionomura/swift:${{ matrix.tag }}
     steps:
       - uses: actions/checkout@v1
       - run: swift test

.github/workflows/xcodebuild.yml

@@ -21,7 +21,7 @@ jobs:
   xcodebuild:
     strategy:
       matrix:
-        xcode_version: ['11.4.1']
+        xcode_version: ['11.3.1', '11.7', '12']
         xcode_flags: ['-scheme Base32 -enableCodeCoverage YES -parallel-testing-enabled NO test']
         xcode_flags_for_build_only: ['-scheme Base32 build']
     runs-on: macOS-10.15