CI: github actions: disable -Wno-deprecated

The deprecrated code is now disabled by default, so we can build with
quictls and openssl 3.0 without this option.
diff --git a/.github/matrix.py b/.github/matrix.py
index 2bd6506..d070ae2 100755
--- a/.github/matrix.py
+++ b/.github/matrix.py
@@ -119,8 +119,6 @@
         flags = ["USE_OPENSSL=1"]
         if ssl == "BORINGSSL=yes" or ssl == "QUICTLS=yes":
             flags.append("USE_QUIC=1")
-        if "OPENSSL_VERSION=3.0." in ssl or ssl == "QUICTLS=yes":
-            flags.append('DEBUG_CFLAGS="-g -Wno-deprecated-declarations"')
         if ssl != "stock":
             flags.append("SSL_LIB=${HOME}/opt/lib")
             flags.append("SSL_INC=${HOME}/opt/include")