Adds ArgoCD 1.7.x acceptance testing (#36)

* Adds ArgoCD 1.7.x acceptance testing

Author: oboukili

.github/workflows/tests.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        argocd_version: ["v1.6.2", "v1.5.8"]
+        argocd_version: ["v1.7.8", "v1.6.2", "v1.5.8"]
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-go@v1