Update default branch from master to main

.github/ISSUE_TEMPLATE/config.yml

@@ -1,7 +1,7 @@
 blank_issues_enabled: false
 contact_links:
   - name: SDK documentation
-    url: https://github.com/box/boxcli/tree/master/docs
+    url: https://github.com/box/boxcli/tree/main/docs
     about: Before creating an issue, I have checked that the SDK documentation doesn't solve my issue.
   - name: API documentation
     url: https://developer.box.com/docs

.travis.yml

@@ -4,7 +4,7 @@ node_js:
 
 branches:
     only:
-        - master
+        - main
 
 script: "npm test"
 after_script: "cat ./coverage/lcov.info | ./node_modules/.bin/coveralls"

CONTRIBUTING.md

@@ -63,7 +63,7 @@ Before sending a pull request, rebase against upstream, such as:
 
 ```
 git fetch upstream
-git rebase upstream/master
+git rebase upstream/main
 ```
 
 This will add your changes on top of what's already in upstream, minimizing merge issues.

package.json

@@ -128,7 +128,7 @@
 		"test": "nyc mocha \"test/**/*.test.js\"",
 		"posttest": "npm run lint",
 		"lint": "eslint --fix ./src ./test",
-		"prepack": "oclif-dev manifest && oclif-dev readme --multi && npm shrinkwrap && git checkout origin/master -- package-lock.json",
+		"prepack": "oclif-dev manifest && oclif-dev readme --multi && npm shrinkwrap && git checkout origin/main -- package-lock.json",
 		"postpack": "rm -f oclif.manifest.json && rm -f npm-shrinkwrap.json",
 		"version": "oclif-dev readme --multi && git add README.md && git add docs",
 		"build": "oclif-dev pack:macos && rm -rf tmp/ && oclif-dev pack:win && rm -rf tmp/ && npm run binaries",