ci: cache go modules and build outputs in workflows

.gitea/workflows/pr-validation.yml

@@ -11,6 +11,7 @@ jobs:
   validate:
     runs-on: ubuntu-latest
     env:
+      RUNNER_TOOL_CACHE: /cache/tools
       ARTEFACT_BUCKET_NAME: ${{ vars.ARTEFACT_BUCKET_NAME }}
       ARTEFACT_BUCKET_ENDPONT: ${{ vars.ARTEFACT_BUCKET_ENDPONT }}
       ARTEFACT_BUCKET_REGION: ${{ vars.ARTEFACT_BUCKET_REGION }}
@@ -27,6 +28,25 @@ jobs:
         with:
           go-version-file: go.mod
 
+      - name: Get go-hashfiles
+        uses: https://gitea.com/actions/go-hashfiles@v0.0.1
+        id: hash-go
+        with:
+          patterns: |-
+            go.mod
+            go.sum
+
+      - name: Cache go
+        id: cache-go
+        uses: https://github.com/actions/cache@v3
+        with:
+          path: |-
+            /root/go/pkg/mod
+            /root/.cache/go-build
+          key: go_cache-${{ steps.hash-go.outputs.hash }}
+          restore-keys: |-
+            go_cache-${{ steps.hash-go.outputs.hash }}
+
       - name: Ensure tooling is available
         run: |
           set -euo pipefail