Use commit URL to calculate the repo slug

When building a fork, `CF_REPO_OWNER` refers to the forked repo instead of the target repo. The only environment variable currently available to derive the correct slug is `CF_COMMIT_URL`.

source/ci_source/providers/Codefresh.ts

@@ -58,9 +58,13 @@ export class Codefresh implements CISource {
   }
 
   get repoSlug(): string {
-    const owner = this.env.CF_REPO_OWNER
-    const reponame = this.env.CF_REPO_NAME
-    return owner && reponame ? `${owner}/${reponame}` : ""
+    const splitSlug = this.env.CF_COMMIT_URL.split("/")
+    if (splitSlug.length === 7) {
+      const owner = splitSlug[3]
+      const reponame = splitSlug[4]
+      return owner && reponame ? `${owner}/${reponame}` : ""
+    }
+    return ""
   }
 
   get ciRunURL() {

source/ci_source/providers/_tests/_codefresh.test.ts

@@ -2,8 +2,7 @@ import { Codefresh } from "../Codefresh"
 import { getCISourceForEnv } from "../../get_ci_source"
 
 const correctEnv = {
-  CF_REPO_OWNER: "codefresh",
-  CF_REPO_NAME: "someproject",
+  CF_COMMIT_URL: "https://github.com/codefresh/someproject/commit/123456",
   CF_BUILD_ID: "1501",
   CF_PULL_REQUEST_NUMBER: "800",
   CF_BUILD_URL: "https://g.codefresh.io/build/1234",
@@ -39,11 +38,10 @@ describe(".isPR", () => {
     expect(codefresh.isPR).toBeFalsy()
   })
 
-  const envs = ["CF_REPO_OWNER", "CF_REPO_NAME", "CF_BUILD_ID", "CF_PULL_REQUEST_NUMBER", "CF_BUILD_URL"]
+  const envs = ["CF_COMMIT_URL", "CF_BUILD_ID", "CF_PULL_REQUEST_NUMBER", "CF_BUILD_URL"]
   envs.forEach((key: string) => {
     let env = {
-      CF_REPO_OWNER: "codefresh",
-      CF_REPO_NAME: "someproject",
+      CF_COMMIT_URL: "https://github.com/codefresh/someproject/commit/123456",
       CF_BUILD_ID: "1501",
       CF_PULL_REQUEST_NUMBER: "800",
       CF_BUILD_URL: "https://g.codefresh.io/build/1234",