export environment variables to github actions

Co-authored-by: rlittlesii <6969701+RLittlesII@users.noreply.github.com>

src/agent/github/build-agent.ts

@@ -168,6 +168,7 @@ class BuildAgent implements IBuildAgent {
 
     public setOutput(name: string, value: string): void {
         core.setOutput(name, value)
+        core.exportVariable(`GITVERSION_${name.toUpperCase()}`, value)
     }
 
     public getInput(input: string, required?: boolean): string {