Update release notes and released version numbers (#1129)

Author: AlmostMatt

cpp_sdk_version.json

@@ -1,5 +1,5 @@
 {
-  "released": "10.0.0",
-  "stable": "10.0.0",
-  "head": "10.0.0"
+  "released": "10.1.0",
+  "stable": "10.1.0",
+  "head": "10.1.0"
 }

release_build_files/readme.md

@@ -634,8 +634,10 @@ workflow use only during the development of your app, not for publicly shipping
 code.
 
 ## Release Notes
-### Upcoming
+### 10.1.0
 -   Changes
+    - General (Android): Update to Firebase Android BoM version 31.0.2.
+    - General (iOS): Update to Firebase Cocoapods version 10.1.0.
     - Firestore (Android): Reduce the number of JNI global references consumed
       when creating or updating documents
       ([#1111](https://github.com/firebase/firebase-cpp-sdk/pull/1111)).