CI: travis-ci: enable weekly graviton2 builds
as documented in https://blog.travis-ci.com/2020-09-11-arm-on-aws
we can build on graviton2, let us expand travis-ci matrix to that
machine type as well
diff --git a/.travis.yml b/.travis.yml
index 2cb2d25..1aa415a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -27,6 +27,12 @@
compiler: gcc
if: type == cron
- os: linux
+ arch: arm64-graviton2
+ group: edge
+ virt: vm
+ compiler: gcc
+ if: type == cron
+ - os: linux
arch: s390x
compiler: gcc
if: type == cron