Prepare next development iteration after release 0.3.0 (#690)

### What's done:
* Versions are updated in pom.xml, README.md and in examples
* Current project version is incremented to the next snapshot

Co-authored-by: GitHub <[email protected]>

README.md

@@ -55,11 +55,11 @@ Main features of diktat are the following:
     # another option is "brew install ktlint"
     ```
 
-2. Load diKTat manually: [here](https://github.com/cqfn/diKTat/releases/download/v0.2.0/diktat.jar)
+2. Load diKTat manually: [here](https://github.com/cqfn/diKTat/releases/download/v0.3.0/diktat.jar)
 
    **OR** use curl:
    ```bash
-   $ curl -sSLO https://github.com/cqfn/diKTat/releases/download/v0.2.0/diktat-0.2.0.jar
+   $ curl -sSLO https://github.com/cqfn/diKTat/releases/download/v0.3.0/diktat-0.3.0.jar
    ```
 
 3. Finally, run KTlint (with diKTat injected) to check your `*.kt` files in `dir/your/dir`:
@@ -110,7 +110,7 @@ This plugin is available since version 0.1.5. You can see how the plugin is conf
 Add this plugin to your `build.gradle.kts`:
 ```kotlin
 plugins {
-    id("org.cqfn.diktat.diktat-gradle-plugin") version "0.2.0"
+    id("org.cqfn.diktat.diktat-gradle-plugin") version "0.3.0"
 }
 ```
 
@@ -121,7 +121,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath("org.cqfn.diktat:diktat-gradle-plugin:0.2.0")
+        classpath("org.cqfn.diktat:diktat-gradle-plugin:0.3.0")
     }
 }
 

diktat-common/pom.xml

@@ -9,7 +9,7 @@
     <parent>
         <groupId>org.cqfn.diktat</groupId>
         <artifactId>diktat-parent</artifactId>
-        <version>0.2.1-SNAPSHOT</version>
+        <version>0.3.1-SNAPSHOT</version>
     </parent>
 
     <dependencies>

diktat-gradle-plugin/gradle-plugin-marker/pom.xml

@@ -4,7 +4,7 @@
     <parent>
         <artifactId>diktat-gradle-plugin</artifactId>
         <groupId>org.cqfn.diktat</groupId>
-        <version>0.2.1-SNAPSHOT</version>
+        <version>0.3.1-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 

diktat-gradle-plugin/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <artifactId>diktat-parent</artifactId>
         <groupId>org.cqfn.diktat</groupId>
-        <version>0.2.1-SNAPSHOT</version>
+        <version>0.3.1-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 

diktat-maven-plugin/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <artifactId>diktat-parent</artifactId>
         <groupId>org.cqfn.diktat</groupId>
-        <version>0.2.1-SNAPSHOT</version>
+        <version>0.3.1-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>
 

diktat-rules/pom.xml

@@ -9,7 +9,7 @@
     <parent>
         <groupId>org.cqfn.diktat</groupId>
         <artifactId>diktat-parent</artifactId>
-        <version>0.2.1-SNAPSHOT</version>
+        <version>0.3.1-SNAPSHOT</version>
     </parent>
 
     <properties>

diktat-ruleset/pom.xml

@@ -8,7 +8,7 @@
     <parent>
         <groupId>org.cqfn.diktat</groupId>
         <artifactId>diktat-parent</artifactId>
-        <version>0.2.1-SNAPSHOT</version>
+        <version>0.3.1-SNAPSHOT</version>
     </parent>
 
     <dependencies>

diktat-test-framework/pom.xml

@@ -9,7 +9,7 @@
     <parent>
         <groupId>org.cqfn.diktat</groupId>
         <artifactId>diktat-parent</artifactId>
-        <version>0.2.1-SNAPSHOT</version>
+        <version>0.3.1-SNAPSHOT</version>
     </parent>
 
     <dependencies>

examples/gradle-groovy-dsl/build.gradle

@@ -1,5 +1,5 @@
 plugins {
-    id "org.cqfn.diktat.diktat-gradle-plugin" version "0.2.0"
+    id "org.cqfn.diktat.diktat-gradle-plugin" version "0.3.0"
 }
 
 repositories {