[SPARK-42641][CONNECT][BUILD] Upgrade buf from 1.14.0 to 1.15.0

### What changes were proposed in this pull request?
Upgrade buf from 1.14.0 to 1.15.0

### Why are the changes needed?
routine upgrade, I manually test and this upgrade will not change the generated files

### Does this PR introduce _any_ user-facing change?
no, dev-only

### How was this patch tested?
manually test and CI

Closes apache#40243 from zhengruifeng/connect_buf_115.

Authored-by: Ruifeng Zheng <[email protected]>
Signed-off-by: Ruifeng Zheng <[email protected]>

Author: zhengruifeng

.github/workflows/build_and_test.yml

@@ -577,7 +577,7 @@ jobs:
     - name: Install dependencies for Python code generation check
       run: |
         # See more in "Installation" https://docs.buf.build/installation#tarball
-        curl -LO https://github.com/bufbuild/buf/releases/download/v1.14.0/buf-Linux-x86_64.tar.gz
+        curl -LO https://github.com/bufbuild/buf/releases/download/v1.15.0/buf-Linux-x86_64.tar.gz
         mkdir -p $HOME/buf
         tar -xvzf buf-Linux-x86_64.tar.gz -C $HOME/buf --strip-components 1
         python3.9 -m pip install 'protobuf==3.19.5' 'mypy-protobuf==3.3.0'

python/docs/source/development/contributing.rst

@@ -120,7 +120,7 @@ Prerequisite
 
 PySpark development requires to build Spark that needs a proper JDK installed, etc. See `Building Spark <https://spark.apache.org/docs/latest/building-spark.html>`_ for more details.
 
-Note that if you intend to contribute to Spark Connect in Python, ``buf`` version ``1.14.0`` is required, see `Buf Installation <https://docs.buf.build/installation>`_ for more details.
+Note that if you intend to contribute to Spark Connect in Python, ``buf`` version ``1.15.0`` is required, see `Buf Installation <https://docs.buf.build/installation>`_ for more details.
 
 Conda
 ~~~~~