ci: get Go version from go.mod

Author: odsod

.github/workflows/ci.yaml

@@ -14,6 +14,8 @@ jobs:
 
       - name: Setup Go
         uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
 
       - name: Build
         run: ./tools/mage build

.github/workflows/release.yaml

@@ -15,6 +15,8 @@ jobs:
 
       - name: Setup Go
         uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
 
       - name: Build
         run: ./tools/mage build