janet-simple: Fix URL

CI everywhere is getting hit by LetsEncrypt's new root CA cert.

Author: ubolonton

.gitmodules

@@ -69,7 +69,7 @@
 	branch = master
 [submodule "repos/janet-simple"]
 	path = repos/janet-simple
-	url = https://codeberg.org/sogaiu/tree-sitter-janet-simple
+	url = https://github.com/sogaiu/tree-sitter-janet-simple
 	update = none
 	ignore = dirty
 	branch = master