Update development.md (#535)

Author: joneugster

doc/development.md

@@ -3,8 +3,10 @@
 ## Updating Lean version
 
 1. make sure `lean-i18n` has been updated
-1. edit `server/lean-toolchain` to contain the desired version: `leanprover/lean4:v4.31.0`
-2. edit all `require` statements in `server/lakefile.lean` to contain the toolchain (e.g. `"v4.31.0"`) instead of `"main"`
-3. call `lake update --keep-toolchain`
-4. undo the changes in `server/lakefile.lean`
-5. `npm run build:server`
+2. edit `server/lean-toolchain` to contain the desired version: `leanprover/lean4:v4.31.0`
+3. edit all `require` statements in `server/lakefile.lean` to contain the toolchain (e.g. `"v4.31.0"`) instead of `"main"`
+4. call `lake update --keep-toolchain`
+5. undo the changes in `server/lakefile.lean`
+6. `npm run build:server`
+7. on github, create a PR and merge it
+8. create a tag, e.g. `v4.31.0`, pointing to the bump commit