Upgrade jupyter-myst-build-proxy to 0.5.1 for bugfix (#42)

Author: mfisher87

docker/environment.yml

@@ -41,7 +41,7 @@ dependencies:
   # Publishing
   - "mystmd"
   - "typst"
-  - "jupyter-myst-build-proxy >=0.5.0"
+  - "jupyter-myst-build-proxy >=0.5.1"
 
   # Testing and validation
   - "ruff"