Pin grand-challenge-forge (#3969)

Next release of forge (v0.7.0) **will** have breaking changes.
Adaptation of those changes will flow via a different PR: meanwhile
pinning will prevent undue breakage when updating dependencies.

Author: chrisvanrun

pyproject.toml

@@ -60,7 +60,7 @@ dependencies = [
     "pyjwt",
     "beautifulsoup4",
     "pymdown-extensions",
-    "grand-challenge-forge",
+    "grand-challenge-forge<=0.6.1",
     "biopython",
     "cachetools",
 ]