[docker] provers: bump alt-ergo to 2.6.3

Author: fdupress

scripts/docker/Dockerfile.build

@@ -16,7 +16,7 @@ COPY --chmod=0755 --chown=1001:0 docker-parts/alt-ergo bin/run-alt-ergo
 ENV PATH="/home/charlie/bin:$PATH"
 
 RUN \
-	version=2.6.2 && \
+	version=2.6.3 && \
 	opam switch create --no-switch alt-ergo-${version} ocaml-system && \
 	opam pin     --switch=alt-ergo-${version} add -n alt-ergo ${version} && \
 	opam install --switch=alt-ergo-${version} --deps-only --confirm-level=unsafe-yes alt-ergo && \