Updating proposal directories to match their PR number (kubernetes-sigs#741)

Author: kfswain

docs/proposals/00x-epp-compliance-proposal/README.md renamed to docs/proposals/0683-epp-architecture-proposal/README.md

@@ -0,0 +1,5 @@
+# Proposals Best Practices
+
+
+## Naming
+The directory of the proposal should lead with a 4-digit PR number (will move to 5,6,... should our PR count get that high), followed by kebab-cased title. The PR number is not known until the PR is cut, so development can use a placeholder, ex. XXXX-my-proposal. PR number is used b/c it is unique & chronological, allowing the default ordering of proposals to follow the timeline of development.