CI/travis/lib.sh: change Travis-CI API endpoint to api.travis-ci.com

We've recently been seeing issues with travis-ci.org; particularly builds
would hang/not-start.
This is bad, since we can no longer be comfortable validating that a change
builds with no errors. So, this would be a bit of a regression in process.

At this point in time, all ADI Github repos have been migrated to
travis-ci.com.
This migration would happen anyway until 31st of December 2020.
The plan we're using is still for Open-Source projects, so no extra cost
should be involved.

This change, switches the API endpoint to 'api.travis-ci.com', so that a
change in libiio propagates to the libad9361-iio, gr-iio, iio-oscilloscope
repos.
Without this, libiio would build, but would not be validated (build-wise)
against these repos.

Some refs:
https://travis-ci.community/t/builds-queuing-for-hours-with-public-git-repo/10351
https://docs.travis-ci.com/user/migrate/open-source-repository-migration#frequently-asked-questions

Signed-off-by: Alexandru Ardelean <[email protected]>

CI/travis/lib.sh

@@ -4,7 +4,7 @@ if [ "$TRIGGER_NEXT_BUILD" = "true" ] && [ "$TRIGGERING_NEXT_BUILD" != "true" ]
 	exit 0
 fi
 
-export TRAVIS_API_URL="https://api.travis-ci.org"
+export TRAVIS_API_URL="https://api.travis-ci.com"
 LOCAL_BUILD_DIR=${LOCAL_BUILD_DIR:-build}
 
 HOMEBREW_NO_INSTALL_CLEANUP=1
@@ -145,7 +145,7 @@ trigger_build() {
 		-H "Travis-API-Version: 3" \
 		-H "Authorization: token $TRAVIS_API_TOKEN" \
 		-d "$body" \
-		"https://api.travis-ci.org/repo/$repo_slug/requests"
+		"${TRAVIS_API_URL}/repo/$repo_slug/requests"
 }
 
 trigger_adi_build() {