Update Kotlin core dependencies to v1.6.21 (#1278)

* Update Kotlin core dependencies to v1.6.21
* Readme updates

Co-authored-by: Andrey Kuleshov <andrewkuleshov7@gmail.com>

README.md

@@ -166,17 +166,22 @@ diktat {
 Also `diktat` extension has different reporters. You can specify `json`, `html`, `sarif`, `plain` (default) or your own custom reporter (it should be added as a dependency into `diktat` configuration):
 ```kotlin
 diktat {
-   reporter = "json" // "html", "json", "plain" (default), "sarif"
+    // since 1.1.0 to keep in line with maven properties
+    reporter = "json" // "html", "json", "plain" (default), "sarif"
+    // before 1.1.0
+    // reporterType = "json" // "html", "json", "plain" (default), "sarif"
 }
 ```
 
-You can also specify an output. 
+You can also specify an output.
 ```kotlin
 diktat {
+    // since 1.1.0 (reporterType for old versions)
     reporter = "json"
     output = "someFile.json"
 }
 ```
+
 </details>
 
 You can run diktat checks using task `diktatCheck` and automatically fix errors with tasks `diktatFix`.
@@ -250,7 +255,7 @@ Diktat can be run via spotless-maven-plugin since version 2.8.0
 </details>
 
 ## GitHub Native Integration
-We suggest everyone to use common ["sarif"](https://docs.oasis-open.org/sarif/sarif/v2.0/sarif-v2.0.html) format as a `reporter` in CI/CD.
+We suggest everyone to use common ["sarif"](https://docs.oasis-open.org/sarif/sarif/v2.0/sarif-v2.0.html) format as a `reporter` (`reporterType`)  in CI/CD.
 GitHub has an [integration](https://docs.github.com/en/code-security/code-scanning/integrating-with-code-scanning/sarif-support-for-code-scanning)
 with SARIF format and provides you a native reporting of diktat issues in Pull Requests.
 

pom.xml

@@ -42,7 +42,7 @@
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <kotlin.version>1.6.10</kotlin.version>
+        <kotlin.version>1.6.21</kotlin.version>
         <kotlin.compiler.incremental>true</kotlin.compiler.incremental>
         <kotlinx.serialization.version>1.3.2</kotlinx.serialization.version>
         <ktlint.version>0.44.0</ktlint.version>