change minimum go version to 1.16, add multiplatform docker image

.github/workflows/build-test.yml

@@ -2,17 +2,17 @@ name: Run Tests
 on:
   push:
     branches:
-      - 'develop'
+      - develop
   pull_request:
     branches:
-      - 'develop'
+      - develop
 jobs:
   build:
     strategy:
       fail-fast: false
       matrix:
         os: [ ubuntu-20.04 ]
-        go: [ '^1.15', '^1.16' ]
+        go: [ '^1.16' ]
         goos: [ linux ]
         goarch: [ amd64, arm64 ]
     runs-on: ${{ matrix.os }}
@@ -60,7 +60,7 @@ jobs:
         run: go test ./...
       - name: Upload Artifact
         uses: actions/upload-artifact@v2
-        if: ${{ matrix.go == '^1.15' && (github.ref == 'refs/heads/develop' || github.event_name == 'pull_request') }}
+        if: ${{ matrix.go == '^1.16' && (github.ref == 'refs/heads/develop' || github.event_name == 'pull_request') }}
         with:
           name: wings_${{ matrix.goos }}_${{ matrix.goarch }}
           path: build/wings_${{ matrix.goos }}_${{ matrix.goarch }}