workflows: cache and don't rebuild everything

Author: dawidd6

.github/workflows/tests.yml

@@ -12,11 +12,18 @@ jobs:
         uses: actions/setup-go@v1
         with:
           go-version: 1.14
+      - name: Cache build
+        uses: actions/cache@v1
+        with:
+          path: ~/.cache/go-build
+          key: ${{runner.os}}-go-${{hashFiles('**/go.sum')}}
+          restore-keys: |
+            ${{runner.os}}-go-
       - name: Install deps
         run: |
           sudo apt-get update
           sudo apt-get install -yq libgtk-3-dev libappindicator3-dev
       - name: Test
         run: |
-          ./build.sh -a -v ./...
+          ./build.sh -v ./...