let github actions build a docker image for testing

.github/workflows/build.yml

@@ -0,0 +1,18 @@
+name: Build
+
+on:
+  push:
+    branches: [ main ]
+
+jobs:
+
+  setup:
+    name: Build
+    runs-on: ubuntu-20.04
+    steps:
+
+    - name: Check out code into the Go module directory
+      uses: actions/checkout@v2
+
+    - name: Build and push the go-gst docker image
+      run: make docker-build docker-push

.github/workflows/tests.yml

@@ -13,32 +13,9 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
 
-    - name: Set up Go 1.15
-      uses: actions/setup-go@v1
-      with:
-        go-version: 1.15
-      id: go
-
     - name: Check out code into the Go module directory
       uses: actions/checkout@v2
 
-    - uses: actions/cache@v1
-      with:
-        path: ~/go/pkg/mod
-        key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
-        restore-keys: |
-          ${{ runner.os }}-go-
-
-    - name: Get dependencies
-      run: |
-        go mod download
-
-    - name: Install gstreamer dependencies
-      run: |
-        sudo apt-get update && sudo DEBIAN_FRONTEND=noninteractive apt-get install -y \
-            libgstreamer1.0-0 libgstreamer1.0-dev libgstreamer-plugins-base1.0-0 libgstreamer-plugins-base1.0-dev \
-            pkg-config build-essential
-
     - name: Lint all packages
       run: |
-        make lint
+        make docker-lint

Makefile

@@ -23,7 +23,7 @@ docker-push: docker-build
 	docker push $(DOCKER_IMAGE)
 
 CMD ?= /bin/bash
-docker-run: docker-build
+docker-run:
 	docker run --rm --privileged \
 	    -v /lib/modules:/lib/modules:ro \
 	    -v /sys:/sys:ro \
@@ -32,5 +32,5 @@ docker-run: docker-build
 		-e HOME=/tmp \
 	    $(DOCKER_IMAGE) $(CMD)
 
-docker-lint: docker-build
+docker-lint:
 	$(MAKE) docker-run CMD="make lint"