bitbake: tests/fetch: Handle upstream master -> main branch change

(Bitbake rev: 38bff0badf916098732fb20210e0ed6d0dd38250)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/tests/fetch.py

@@ -993,7 +993,7 @@ class FetcherNetworkTest(FetcherTest):
         """ Prevent regression on deeply nested submodules not being checked out properly, even though they were fetched. """
 
         # This repository also has submodules where the module (name), path and url do not align
-        url = "gitsm://github.com/azure/iotedge.git;protocol=git;rev=d76e0316c6f324345d77c48a83ce836d09392699"
+        url = "gitsm://github.com/azure/iotedge.git;protocol=git;rev=d76e0316c6f324345d77c48a83ce836d09392699;branch=main"
         fetcher = bb.fetch.Fetch([url], self.d)
         fetcher.download()
         # Previous cwd has been deleted