fix references of master branch

.github/pull_request_template.md

@@ -1,6 +1,6 @@
 * Link the PR to the related issue
 * If there's no issue for the PR, please, create it first
-* Rebase your PR if it gets out of sync with master
+* Rebase your PR if it gets out of sync with main
 * Ensure your PR does not include dist/ directory
 
 **REMOVE THE TEXT ABOVE BEFORE CREATING THE PULL REQUEST**

README.md

@@ -1,7 +1,7 @@
 # Zabbix plugin for Grafana
 
 [![Version](https://badge.fury.io/gh/grafana%2Fgrafana-zabbix.svg)](https://github.com/grafana/grafana-zabbix/releases)
-[![Change Log](https://img.shields.io/badge/change-log-blue.svg?style=flat)](https://github.com/grafana/grafana-zabbix/blob/master/CHANGELOG.md)
+[![Change Log](https://img.shields.io/badge/change-log-blue.svg?style=flat)](https://github.com/grafana/grafana-zabbix/blob/main/CHANGELOG.md)
 [![Docs](https://img.shields.io/badge/docs-latest-red.svg?style=flat)](https://grafana.com/docs/plugins/alexanderzobnin-zabbix-app/latest/)
 
 ![Dashboard](https://user-images.githubusercontent.com/4932851/53799185-e1cdc700-3f4a-11e9-9cb4-8330f501b32e.png)

docs/sources/installation.md

@@ -49,4 +49,4 @@ Starting from version 4.0, each plugin release on GitHub contains packaged plugi
 
 ## Building from sources
 
-If you want to build a package yourself, or contribute - read [building instructions](./run_from_master).
+If you want to build a package yourself, or contribute - read [building instructions](./run-from-main).