clarify contribute

CONTRIBUTE.md

@@ -2,14 +2,12 @@
 
 ## Branches
 
-* `2.x.x` main line for 2.x.x
-* `3.x.x` actual main line
+* `2.x.x` main line for `2.x.x`
+* `3.x.x` main line for `3.x.x`
     * documentation links refer to `3.x.x`
     * 2.x.x can be merged to 3.x.x
 * `main`
-    * documentation links refer to `latest`
-    * 3.x.x can be merged to main
-* `stable` main line for 2.x.x with release tags
+    * 2.x.x can be merged to main
 
 ## Testing
 
@@ -47,15 +45,6 @@ git checkout 3.x.x
 git pull origin 2.x.x
 git push origin 3.x.x
 
-# Update main
-git checkout main
-git pull origin 3.x.x
-git push origin main
-
-# Update release branch - currently 2.x.x
-git checkout stable
-git pull origin 2.x.x
-
 prev_version=$(poetry version -s)
 
 # Version Bump
@@ -74,5 +63,10 @@ git tag "${version}" -m "Release ${version}"
 git push
 git push --tags
 
+# Update main
+git checkout main
+git pull origin 2.x.x
+git push origin main
+
 # Publishing is handled by CI
 ```