chore: simplify CI build matrix

Although we originally thought this would be a useful way to do this, it
doesn't enforce the `go.mod` constraints that we'd hoped it would, as
Renovate could bump the `go.mod`'s `go` directive, and it means that we
have a more explicit, and less magic, setup.

Additionally, we need to quote the versions as `1.20` gets interpreted
by YAML as `1.2` 🙃

.github/workflows/ci.yml

@@ -8,21 +8,17 @@ jobs:
       fail-fast: false
       # perform matrix testing to give us an earlier insight into issues with different versions of supported major versions of Go
       matrix:
-        # strategy is used to allow us to pin to a specific Go version, or use the version available in our `go.mod`
-        strategy: ['go-version']
-        version: [1.21]
-        include:
-          # pick up the Go version from the `go.mod`
-          - strategy: 'go-version-file'
-            version: 'go.mod'
+        version:
+        - "1.20"
+        - "1.21"
     steps:
       - name: Check out source code
         uses: actions/checkout@v3
 
       - name: Set up Go
         uses: actions/setup-go@v3
         with:
-          ${{ matrix.strategy }}: ${{ matrix.version }}
+          go-version: ${{ matrix.version }}
 
       - name: Test
         run: make test

.github/workflows/generate.yml

@@ -8,21 +8,17 @@ jobs:
       fail-fast: false
       # perform matrix testing to give us an earlier insight into issues with different versions of supported major versions of Go
       matrix:
-        # strategy is used to allow us to pin to a specific Go version, or use the version available in our `go.mod`
-        strategy: ['go-version']
-        version: [1.21]
-        include:
-          # pick up the Go version from the `go.mod`
-          - strategy: 'go-version-file'
-            version: 'go.mod'
+        version:
+        - "1.20"
+        - "1.21"
     steps:
       - name: Check out source code
         uses: actions/checkout@v3
 
       - name: Set up Go
         uses: actions/setup-go@v3
         with:
-          ${{ matrix.strategy }}: ${{ matrix.version }}
+          go-version: ${{ matrix.version }}
 
       - name: Run `make generate`
         run: make generate

.github/workflows/lint.yml

@@ -8,21 +8,17 @@ jobs:
       fail-fast: false
       # perform matrix testing to give us an earlier insight into issues with different versions of supported major versions of Go
       matrix:
-        # strategy is used to allow us to pin to a specific Go version, or use the version available in our `go.mod`
-        strategy: ['go-version']
-        version: [1.21]
-        include:
-          # pick up the Go version from the `go.mod`
-          - strategy: 'go-version-file'
-            version: 'go.mod'
+        version:
+        - "1.20"
+        - "1.21"
     steps:
       - name: Check out source code
         uses: actions/checkout@v3
 
       - name: Set up Go
         uses: actions/setup-go@v3
         with:
-          ${{ matrix.strategy }}: ${{ matrix.version }}
+          go-version: ${{ matrix.version }}
 
       - name: Run `make lint-ci`
         run: make lint-ci

.github/workflows/tidy.yml

@@ -8,21 +8,17 @@ jobs:
       fail-fast: false
       # perform matrix testing to give us an earlier insight into issues with different versions of supported major versions of Go
       matrix:
-        # strategy is used to allow us to pin to a specific Go version, or use the version available in our `go.mod`
-        strategy: ['go-version']
-        version: [1.21]
-        include:
-          # pick up the Go version from the `go.mod`
-          - strategy: 'go-version-file'
-            version: 'go.mod'
+        version:
+        - "1.20"
+        - "1.21"
     steps:
       - name: Check out source code
         uses: actions/checkout@v3
 
       - name: Set up Go
         uses: actions/setup-go@v3
         with:
-          ${{ matrix.strategy }}: ${{ matrix.version }}
+          go-version: ${{ matrix.version }}
 
       - name: Install `tidied`
         run: go install gitlab.com/jamietanna/tidied@latest