Update Go version, fix duplicate runs.

.github/workflows/test.yml

@@ -1,6 +1,11 @@
 name: Test
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - master
+      - develop
+  pull_request:
 
 jobs:
   build:
@@ -10,7 +15,7 @@ jobs:
     - name: Set up Go 1.x
       uses: actions/setup-go@v2
       with:
-        go-version: ^1.14
+        go-version: ^1.15
       id: go
 
     - name: Check out code into the Go module directory