✨ Support new default branch

See https://github.com/github/renaming#on-october-1-2020-newly-created-repositories-will-default-to-main

entrypoint.sh

@@ -115,11 +115,11 @@ hasCustomTag() {
 }
 
 isOnDefaultBranch() {
-  local DEFAULT_BRANCH="master"
   if uses "${INPUT_DEFAULT_BRANCH}"; then
-    DEFAULT_BRANCH="${INPUT_DEFAULT_BRANCH}"
+    [ "${BRANCH}" = "${INPUT_DEFAULT_BRANCH}" ]
+  else
+    [ "${BRANCH}" = "master" ] || [ "${BRANCH}" = "main" ]
   fi
-  [ "${BRANCH}" = "${DEFAULT_BRANCH}" ]
 }
 
 isGitTag() {

test.bats

@@ -25,6 +25,20 @@ teardown() {
   unset MOCK_ERROR_CONDITION
 }
 
+@test "it pushes main branch to latest" {
+  export GITHUB_REF='refs/heads/main'
+
+  run /entrypoint.sh
+
+  expectStdOutContains "::set-output name=tag::latest"
+
+  expectMockCalledContains "/usr/local/bin/docker login -u USERNAME --password-stdin
+/usr/local/bin/docker build -t my/repository:latest .
+/usr/local/bin/docker push my/repository:latest
+/usr/local/bin/docker inspect --format={{index .RepoDigests 0}} my/repository:latest
+/usr/local/bin/docker logout"
+}
+
 @test "it pushes master branch to latest" {
   export GITHUB_REF='refs/heads/master'