apply the syntax

src/deployment.js

@@ -25,7 +25,7 @@ class Deployment {
       this.workflowRun = context.workflowRun
       this.requestedDeployment = false
       this.deploymentInfo = null
-      this.githubApiUrl = context.githubApiUrl
+      this.githubApiUrl = process.env.GITHUB_API_URL ? process.env.GITHUB_API_URL : "https://api.github.com",
       this.artifactName = core.getInput('artifact_name')
     }