chore: Publish in our repository

Motivation:
Official repository published to bintray that was sunset.

Modifications:
 * Remove bintray dependencies
 * Force version
 * Upgrade dependencies

Result:
Published in our own repository until official contributors take a decision.

Ref: OpenAPITools#35

build.sbt

@@ -13,46 +13,33 @@ lazy val `sbt-openapi-generator` = (project in file("."))
     crossScalaVersions := Seq(scalaVersion.value, "2.11.12"),
     crossSbtVersions := List("0.13.17", "1.3.10"),
     sbtPlugin := true,
-
-    publishMavenStyle := false,
-
-    bintrayRepository := "sbt-plugins",
-    bintrayOrganization := Option("openapitools"),
-    bintrayPackageLabels := Seq("sbt", "plugin", "oas", "openapi", "openapi-generator"),
-    bintrayVcsUrl := Some("git@github.com:OpenAPITools/sbt-openapi-generator.git"),
-
+    publishMavenStyle := true,
     scriptedLaunchOpts := {
       scriptedLaunchOpts.value ++ Seq("-Xmx1024M", "-server", "-Dplugin.version=" + version.value)
     },
-
     scriptedBufferLog := false,
-
     resolvers ++= Seq(
       Resolver.sbtPluginRepo("snapshots"),
       Resolver.sonatypeRepo("snapshots")
     ),
-
     homepage := Some(url("https://openapi-generator.tech")),
-
     organization := "org.openapitools",
     organizationName := "OpenAPI-Generator Contributors",
     organizationHomepage := Some(url("https://github.com/OpenAPITools")),
-
     licenses += ("The Apache Software License, Version 2.0", url("https://www.apache.org/licenses/LICENSE-2.0.txt")),
-
     developers += Developer(
       id = "openapitools",
       name = "OpenAPI-Generator Contributors",
       email = "team@openapitools.org",
       url = url("https://github.com/OpenAPITools")
     ),
-
     scmInfo := Some(
       ScmInfo(
         browseUrl = url("https://github.com/OpenAPITools/openapi-generator"),
         connection = "scm:git:git://github.com/OpenAPITools/openapi-generator.git",
-        devConnection = "scm:git:ssh://git@github.com:OpenAPITools/openapi-generator.git")
+        devConnection = "scm:git:ssh://git@github.com:OpenAPITools/openapi-generator.git"
+      )
     ),
-
-    libraryDependencies += "org.openapitools" % "openapi-generator" % "5.1.0"
-  ).enablePlugins(SbtPlugin)
+    libraryDependencies += "org.openapitools" % "openapi-generator" % "5.2.1"
+  )
+  .enablePlugins(SbtPlugin)

project/plugin.sbt

@@ -1,5 +0,0 @@
-// Manages publishing.
-addSbtPlugin("org.foundweekends" % "sbt-bintray" % "0.5.6")
-
-// Versions the build.
-addSbtPlugin("com.dwijnand" % "sbt-dynver" % "4.1.1")

version.sbt

@@ -0,0 +1,2 @@
+ThisBuild / version := "5.2.1"
+ThisBuild / isSnapshot := false