configure: align libplacebo version check with reality

This filter already failed to compile on older versions, because of an
unconditional use of an API introduced in API version 220. Nobody noticed
this, so I conclude that it's safe to bump the required version by now.

configure

@@ -7018,7 +7018,7 @@ enabled libopus           && {
         require_pkg_config libopus opus opus_multistream.h opus_multistream_surround_encoder_create
     }
 }
-enabled libplacebo        && require_pkg_config libplacebo "libplacebo >= 4.192.0" libplacebo/vulkan.h pl_vulkan_create
+enabled libplacebo        && require_pkg_config libplacebo "libplacebo >= 5.229.0" libplacebo/vulkan.h pl_vulkan_create
 enabled libpulse          && require_pkg_config libpulse libpulse pulse/pulseaudio.h pa_context_new
 enabled libqrencode       && require_pkg_config libqrencode libqrencode qrencode.h QRcode_encodeString
 enabled libquirc          && require libquirc quirc.h quirc_decode -lquirc