Fixing CI/CD for diktat and detekt (#102)

### What's done:
- diktat action updated to main branch
- detekt action updated to main branch

.github/workflows/detekt.yml

@@ -2,7 +2,7 @@ name: Run deteKT
 
 on:
   push:
-    branches: [ master ]
+    branches: [ main ]
   pull_request:
 
 jobs:

.github/workflows/diktat.yml

@@ -2,7 +2,7 @@ name: Run diKTat
 
 on:
   push:
-    branches: [ master ]
+    branches: [ main ]
   pull_request:
 
 jobs:

README.md

@@ -9,8 +9,8 @@
 ![GitHub repo size](https://img.shields.io/github/repo-size/akuleshov7/ktoml)
 ![codebeat badge](https://codebeat.co/badges/0518ea49-71ed-4bfd-8dd3-62da7034eebd)
 ![maintainability](https://api.codeclimate.com/v1/badges/c75d2d6b0d44cea7aefe/maintainability)
-![Run deteKT](https://github.com/akuleshov7/ktoml/actions/workflows/detekt.yml/badge.svg)
-![Run diKTat](https://github.com/akuleshov7/ktoml/actions/workflows/diktat.yml/badge.svg)
+![Run deteKT](https://github.com/akuleshov7/ktoml/actions/workflows/detekt.yml/badge.svg?branch=main)
+![Run diKTat](https://github.com/akuleshov7/ktoml/actions/workflows/diktat.yml/badge.svg?branch=main)
 
 Fully Native and Multiplatform Kotlin serialization library for serialization/deserialization of [toml](https://toml.io/en/) format.
 Uses native [kotlinx.serialization](https://github.com/Kotlin/kotlinx.serialization), provided by Kotlin. This library contains no Java code and no Java dependencies.