docs: update default branch to main

.circleci/config.yml

@@ -41,7 +41,7 @@ jobs:
           path: .build
           destination: /build
 
-  docker_hub_master:
+  docker_hub_main:
     executor: golang
 
     steps:
@@ -99,13 +99,13 @@ workflows:
           filters:
             tags:
               only: /.*/
-      - docker_hub_master:
+      - docker_hub_main:
           requires:
             - test
             - build
           filters:
             branches:
-              only: master
+              only: main
       - docker_hub_release_tags:
           requires:
             - test

README.md

@@ -1,6 +1,6 @@
 # SNMP Notifier [![Build Status](https://travis-ci.org/maxwo/snmp_notifier.svg?branch=master)](https://travis-ci.org/maxwo/snmp_notifier)
 
-[![CircleCI](https://circleci.com/gh/maxwo/snmp_notifier/tree/master.svg?style=svg)](https://circleci.com/gh/maxwo/snmp_notifier/tree/master)
+[![CircleCI](https://circleci.com/gh/maxwo/snmp_notifier/tree/main.svg?style=svg)](https://circleci.com/gh/maxwo/snmp_notifier/tree/master)
 [![Go Report Card](https://goreportcard.com/badge/github.com/maxwo/snmp_notifier)](https://goreportcard.com/report/github.com/maxwo/snmp_notifier)
 
 `snmp_notifier` receives alerts from the Prometheus' Alertmanager and routes them as SNMP traps.