chore(ci): new minimum for all android versions is 21

Author: Green-Sky

.github/scripts/cmake-android

@@ -10,15 +10,15 @@ ABI=${1:-"armeabi-v7a"}
 case $ABI in
   armeabi-v7a)
     TARGET=armv7a-linux-androideabi
-    NDK_API=19
+    NDK_API=21
     ;;
   arm64-v8a)
     TARGET=aarch64-linux-android
     NDK_API=21
     ;;
   x86)
     TARGET=i686-linux-android
-    NDK_API=19
+    NDK_API=21
     ;;
   x86_64)
     TARGET=x86_64-linux-android