Drop Go 1.15 from unit tests

Author: willianpaixao

.github/workflows/unit-tests.yml

@@ -7,13 +7,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go: [1.15, 1.16]
+        go: [1.16]
         os: [ubuntu-latest, macos-latest, windows-latest]
         make_target: [test]
 
     steps:
     - name: Set up Go
-      uses: actions/setup-go@v2.1.3
+      uses: actions/setup-go@v2
       with:
         go-version: ${{ matrix.go }}
       id: go