tox.ini (envlist): Replace docker-ubuntu-trusty-minimal with docker-ubuntu-trusty-toolchain-gcc_9-minimal

Author: Matthias Koeppe

tox.ini

@@ -55,7 +55,7 @@ envlist =
     ### - standard  # Install all known system packages equivalent to standard packages that have spkg-configure.m4
     ### - maximal   # Install all known system packages equivalent to standard/optional packages that have spkg-configure.m4
 
-    docker-ubuntu-trusty-minimal,
+    docker-ubuntu-trusty-toolchain-gcc_9-minimal,
     docker-debian-bullseye-standard,
     docker-fedora-34-standard,
     docker-archlinux-latest-maximal,