app-containers/buildah: mask 1.34.0 for amd64 (arm64 first must stabilize 1.33.x)

Masking because it isn't getting security fixes from upstream and seems
like 1.34.x is more suitable for podman 5.x (yet to be released)

https://github.com/containers/buildah/issues/5320

Bug: https://bugs.gentoo.org/924456
From: https://github.com/gentoo/gentoo/pull/35261
Signed-off-by: Zac Medico <zmedico@gentoo.org>

app-containers/buildah/buildah-1.34.0.ebuild

@@ -29,7 +29,7 @@ if [[ ${PV} == 9999* ]]; then
 	EGIT_REPO_URI="https://github.com/containers/buildah.git"
 else
 	SRC_URI="https://github.com/containers/buildah/archive/v${PV}.tar.gz -> ${P}.tar.gz"
-	KEYWORDS="amd64 arm64"
+	KEYWORDS="arm64"
 fi
 
 RDEPEND="