build: require gcc >= 9.1, recommend gcc >= 10.2

Similarly, recommend clang 10 or later. On macOS, the minimum Xcode
version is now 11, the recommended one is still 13 or later.

Change-Id: Ia801b189537a054126e8066d9b6ee9c8df2b5cb2
diff --git a/.jenkins.d/00-deps.sh b/.jenkins.d/00-deps.sh
index dc9eadb..b5fb9a8 100755
--- a/.jenkins.d/00-deps.sh
+++ b/.jenkins.d/00-deps.sh
@@ -18,7 +18,7 @@
     pkg-config
     python3
 )
-FORMULAE=(boost openssl pkg-config)
+FORMULAE=(boost openssl pkgconf)
 PIP_PKGS=()
 case $JOB_NAME in
     *code-coverage)