ci: increase available ccache size to 300MB

Author: m3dwards

ci/test/00_setup_env_native_asan.sh

@@ -26,3 +26,4 @@ export BITCOIN_CONFIG="--enable-usdt --enable-zmq --with-incompatible-bdb --with
 CPPFLAGS='-DARENA_DEBUG -DDEBUG_LOCKORDER' \
 --with-sanitizers=address,float-divide-by-zero,integer,undefined \
 CC='clang-18 -ftrivial-auto-var-init=pattern' CXX='clang++-18 -ftrivial-auto-var-init=pattern'"
+export CCACHE_MAXSIZE=300M