CI: update to NDK r27d, add r29

Author: triplef

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ macos-latest, ubuntu-latest ]
-        ndk: [ r25c, r26d, r27c ]
+        ndk: [ r25c, r26d, r27d, r29 ]
 
     env:
       ANDROID_DIR: ${{ startsWith(matrix.os, 'macos-') && 'Library/Android' || 'Android' }}