(IAC-1026) - Update default travis/appveyor branches from master to main

.travis.yml

@@ -11,7 +11,7 @@ script:
   - ".travis/test_script.sh"
 branches:
   only:
-    - master
+    - main
 notifications:
   email: false
   slack:

config_defaults.yml

@@ -84,7 +84,7 @@ common:
       rvm: 2.5.7
       stage: spec
   branches:
-    - master
+    - main
     - /^v\d/
   use_litmus: false
   use_litmus_complex: false
@@ -121,7 +121,7 @@ appveyor.yml:
   test_script:
     - bundle exec rake %CHECK%
   branches:
-    - master
+    - main
     - release
 Rakefile:
   changelog_version_tag_pattern: 'v%s'