Rename various references to master branch

diff --git a/.ci/deploy-docs.sh b/.ci/deploy-docs.sh
index 854ca23..a8efb2a 100755
--- a/.ci/deploy-docs.sh
+++ b/.ci/deploy-docs.sh

@@ -23,12 +23,12 @@
 git remote add upstream "https://$GH_TOKEN@github.com/harfbuzz/harfbuzz.github.io.git"
 set -x
 git fetch upstream
-git reset upstream/master
+git reset upstream/main
 
 touch .
 git add -A .
 
 if [[ $(git status -s) ]]; then
   git commit -m "Rebuild docs for https://github.com/harfbuzz/harfbuzz/commit/$REVISION"
-  git push -q upstream HEAD:master
+  git push -q upstream HEAD:main
 fi

diff --git a/.github/workflows/linux-ci.yml b/.github/workflows/linux-ci.yml
index b780451..88b1f59 100644
--- a/.github/workflows/linux-ci.yml
+++ b/.github/workflows/linux-ci.yml

@@ -2,9 +2,9 @@
 
 on:
   push:
-    branches: [ master ]
+    branches: [ main ]
   pull_request:
-    branches: [ master ]
+    branches: [ main ]
 
 jobs:
   build:
@@ -23,7 +23,7 @@
     - name: generate documentations
       run: ninja -Cbuild harfbuzz-doc
     - name: deploy documentations
-      if: github.event_name == 'push' && github.ref == 'refs/heads/master'
+      if: github.event_name == 'push' && github.ref == 'refs/heads/main'
       run: .ci/deploy-docs.sh
       env:
         GH_TOKEN: ${{ secrets.GH_TOKEN }}

diff --git a/.github/workflows/msvc-ci.yml b/.github/workflows/msvc-ci.yml
index 2dd722e..7c9f5bc 100644
--- a/.github/workflows/msvc-ci.yml
+++ b/.github/workflows/msvc-ci.yml

@@ -2,9 +2,9 @@
 
 on:
   push:
-    branches: [ master ]
+    branches: [ main ]
   pull_request:
-    branches: [ master ]
+    branches: [ main ]
 
 jobs:
   msvc:

diff --git a/.github/workflows/msys2-ci.yml b/.github/workflows/msys2-ci.yml
index 26a3dfe..b8b2fc3 100644
--- a/.github/workflows/msys2-ci.yml
+++ b/.github/workflows/msys2-ci.yml

@@ -2,9 +2,9 @@
 
 on:
   push:
-    branches: [ master ]
+    branches: [ main ]
   pull_request:
-    branches: [ master ]
+    branches: [ main ]
 
 jobs:
   msys2:

diff --git a/README b/README
index f4d2294..84c542f 100644
--- a/README
+++ b/README

@@ -4,12 +4,12 @@
 
   http://harfbuzz.org/
 
-For license information, see https://github.com/harfbuzz/harfbuzz/blob/master/COPYING
+For license information, see https://github.com/harfbuzz/harfbuzz/blob/main/COPYING
 
-For build information, see https://github.com/harfbuzz/harfbuzz/blob/master/BUILD.md
+For build information, see https://github.com/harfbuzz/harfbuzz/blob/main/BUILD.md
 
-For custom configurations, see https://github.com/harfbuzz/harfbuzz/blob/master/CONFIG.md
+For custom configurations, see https://github.com/harfbuzz/harfbuzz/blob/main/CONFIG.md
 
-For test execution, see https://github.com/harfbuzz/harfbuzz/blob/master/TESTING.md
+For test execution, see https://github.com/harfbuzz/harfbuzz/blob/main/TESTING.md
 
 Documentation: https://harfbuzz.github.io

diff --git a/README.md b/README.md
index 0df556d..9deb32c 100644
--- a/README.md
+++ b/README.md

@@ -1,9 +1,9 @@
 [![Linux CI Status](https://github.com/harfbuzz/harfbuzz/workflows/linux-ci/badge.svg)](https://github.com/harfbuzz/harfbuzz/workflows/linux-ci/badge.svg)
-[![CircleCI Build Status](https://circleci.com/gh/harfbuzz/harfbuzz/tree/master.svg?style=svg)](https://circleci.com/gh/harfbuzz/harfbuzz/tree/master)
+[![CircleCI Build Status](https://circleci.com/gh/harfbuzz/harfbuzz/tree/main.svg?style=svg)](https://circleci.com/gh/harfbuzz/harfbuzz/tree/main)
 [![OSS-Fuzz Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/harfbuzz.svg)](https://oss-fuzz-build-logs.storage.googleapis.com/index.html)
 [![Coverity Code Health](https://img.shields.io/coverity/scan/5450.svg)](https://scan.coverity.com/projects/behdad-harfbuzz)
 [![Codacy Code Health](https://api.codacy.com/project/badge/Grade/f17f1708783c447488bc8dd317150eaa)](https://app.codacy.com/app/behdad/harfbuzz)
-[![Codecov Code Coverage](https://codecov.io/gh/harfbuzz/harfbuzz/branch/master/graph/badge.svg)](https://codecov.io/gh/harfbuzz/harfbuzz)
+[![Codecov Code Coverage](https://codecov.io/gh/harfbuzz/harfbuzz/branch/main/graph/badge.svg)](https://codecov.io/gh/harfbuzz/harfbuzz)
 [![Coverals Code Coverage](https://img.shields.io/coveralls/harfbuzz/harfbuzz.svg)](https://coveralls.io/r/harfbuzz/harfbuzz)
 [![Packaging status](https://repology.org/badge/tiny-repos/harfbuzz.svg)](https://repology.org/project/harfbuzz/versions)
 [ABI Tracker](http://abi-laboratory.pro/tracker/timeline/harfbuzz/)