Split CI unit tests into supported and deprecated Go version stages (#…

…368)

Splits the GitHub Action CI unit tests for Go into two different
sections, version supported by Go, and deprecated. This allows the unit
tests to fail faster on cross version issues, and separate deprecated
Go versions into a separate group.

.github/workflows/go.yml

@@ -8,12 +8,12 @@ on:
 
 jobs:
   unit-tests:
-    name: Test SDK
+    name: SDK Unit Tests
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        go-version: [1.17, 1.16, 1.15]
+        go-version: [1.18, 1.17]
     steps:
     - uses: actions/checkout@v2
 
@@ -25,3 +25,21 @@ jobs:
     - name: Test
       run: go test -v ./...
 
+  deprecated-unit-tests:
+    needs: unit-tests
+    name: Deprecated Go version SDK Unit Tests
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        go-version: [1.16, 1.15]
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: ${{ matrix.go-version }}
+
+    - name: Test
+      run: go test -v ./...