Avoid set-env environment warning during build log generation

Author: danielmarbach

src/GitVersionCore/BuildAgents/GitHubActions.cs

@@ -33,7 +33,7 @@ public override string[] GenerateSetParameterMessage(string name, string value)
 
                 return new[]
                 {
-                    $"::set-env name={key}::{value}"
+                    $""{name}={value}" >> $GITHUB_ENV"
                 };
             }