Add "see more" link to GHE-not-supported warning (#609)

* Add "see more" link to GHE-not-supported warning

I lived for several months thinking that support for caching action on GHE is just a matter of time, because it's such an important thing to have. Only today, I discovered that originally it was not planned at all. And that people already created some workarounds. So I hope that linking the issue from the warning message will save other people from what happened to me :-)

* Update new GHE-not-supported message in tests

* Update generated dist files

__tests__/restore.test.ts

@@ -68,7 +68,7 @@ test("restore on GHES should no-op", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledTimes(1);
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(false);
     expect(logWarningMock).toHaveBeenCalledWith(
-        "Cache action is not supported on GHES"
+        "Cache action is not supported on GHES. See https://github.com/actions/cache/issues/505 for more details"
     );
 });
 

__tests__/save.test.ts

@@ -111,7 +111,7 @@ test("save on GHES should no-op", async () => {
 
     expect(saveCacheMock).toHaveBeenCalledTimes(0);
     expect(logWarningMock).toHaveBeenCalledWith(
-        "Cache action is not supported on GHES"
+        "Cache action is not supported on GHES. See https://github.com/actions/cache/issues/505 for more details"
     );
 });