build: update waf to version 2.0.23

Change-Id: I2afeee792c0b6627d979c7c175862ae25507599b
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e988485..d9f98d8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -51,7 +51,7 @@
         include:
           - xcode: '12.5'
             os: macos-11
-          - xcode: '13'
+          - xcode: '13.2'
             os: macos-11
     runs-on: ${{ matrix.os }}
     env: