add functional tests to github actions

.github/workflows/functional.yml

@@ -0,0 +1,31 @@
+name: functional tests
+on: pull_request
+jobs:
+
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+
+    - name: Set up Go
+      uses: actions/setup-go@v4
+      with:
+        go-version: 'stable'
+      id: go
+
+    - name: Check out code into the Go module directory
+      uses: actions/checkout@v3
+
+    - name: Get dependencies
+      run: |
+        go get -v -t -d ./...
+
+    - name: Build
+      run: make
+
+    - name: Test
+      run: |
+        mkdir /tmp/gw
+        ./versitygw -a user -s pass posix /tmp/gw &
+        sleep 1
+        ./versitygw test -a user -s pass -e http://127.0.0.1:7070 full-flow