chore: rename master -> main in CI and scripts (#246)

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platform/linux/scripts/after_success.sh

@@ -3,7 +3,7 @@
 set -e
 set -o pipefail
 
-if [ "${TRAVIS_PULL_REQUEST_BRANCH:-${TRAVIS_BRANCH}}" = "master" ] && [ "${BUILDTYPE}" = "Release" ]; then
+if [ "${TRAVIS_PULL_REQUEST_BRANCH:-${TRAVIS_BRANCH}}" = "main" ] && [ "${BUILDTYPE}" = "Release" ]; then
     CLOUDWATCH=true platform/linux/scripts/metrics.sh
 else
     echo "Not logging binary size for branch or Debug build"