Add sbt-release plugin

This PR adds sbt-release which helps automate release process
by just sbt release with-defaults. It'll bump current version
and create corresponding tag.

README.md

@@ -44,3 +44,9 @@ Run code format and auto code refactor with scalafmt & scalafix:
 ```sh
 sbt prepare
 ```
+
+### release
+
+```bash
+sbt release with-defaults
+```

build.sbt

@@ -4,7 +4,6 @@ inThisBuild(
   Seq(
     scalaVersion  := "3.4.2",
     versionScheme := Some("early-semver"),
-    version       := "3.0",
     run / fork    := true,
     run / javaOptions += "-Dconfig.override_with_env_vars=true",
     semanticdbEnabled  := true, // for scalafix

project/BuildPlugin.scala

@@ -0,0 +1,30 @@
+import sbt._, Keys._
+import sbt.ScriptedPlugin.autoImport._
+import sbtrelease.ReleasePlugin, ReleasePlugin.autoImport._, ReleaseTransformations._, ReleaseKeys._
+import sbt.ScriptedPlugin.autoImport._
+
+import sbt.plugins.{JvmPlugin, SbtPlugin}
+
+object BuildPlugin extends AutoPlugin {
+  override def trigger = allRequirements
+
+  override def requires = ReleasePlugin
+
+  override lazy val projectSettings = releaseSettings
+
+  def releaseSettings: Seq[Setting[_]] =
+    Seq(
+      releaseProcess := Seq[ReleaseStep](
+        checkSnapshotDependencies,
+        inquireVersions,
+        runClean,
+        runTest,
+        setReleaseVersion,
+        commitReleaseVersion,
+        tagRelease,
+        setNextVersion,
+        commitNextVersion,
+        pushChanges
+      )
+    )
+}

project/plugins.sbt

@@ -5,3 +5,4 @@ addSbtPlugin("org.scalameta"  % "sbt-scalafmt"        % "2.5.2")
 addSbtPlugin("org.typelevel"  % "sbt-tpolecat"        % "0.5.1")
 addSbtPlugin("ch.epfl.scala"  % "sbt-scalafix"        % "0.12.1")
 addSbtPlugin("nl.gn0s1s"      % "sbt-dotenv"          % "3.0.0")
+addSbtPlugin("com.github.sbt" % "sbt-release"         % "1.4.0")

version.sbt

@@ -0,0 +1 @@
+ThisBuild / version := "3.0.0"