Bump tlBaseVersion to 0.15 (#401)

* Bump tlBaseVersion to 0.15
  - Update past versions
* Remove tlBaseVersionIntroduced

build.sbt

@@ -1,4 +1,4 @@
-ThisBuild / tlBaseVersion := "0.14"
+ThisBuild / tlBaseVersion := "1.15"
 ThisBuild / circeRootOfCodeCoverage := None
 ThisBuild / startYear := Some(2016)
 ThisBuild / scalafixScalaBinaryVersion := "2.12"
@@ -13,7 +13,7 @@ val Versions = new {
   val scalaTestPlus = "3.2.14.0"
   val snakeYaml = "2.2"
   val snakeYamlEngine = "2.7"
-  val previousCirceYamls = Set("0.14.0", "0.14.1", "0.14.2")
+  val previousCirceYamls = Set("0.14.0", "0.14.1", "0.14.2", "0.15.0")
 
   val scala212 = "2.12.18"
   val scala213 = "2.13.12"
@@ -37,8 +37,7 @@ lazy val `circe-yaml-common` = project
     description := "Library for converting between SnakeYAML's AST (YAML 1.1) and circe's AST",
     libraryDependencies ++= Seq(
       "io.circe" %% "circe-core" % Versions.circe
-    ),
-    tlVersionIntroduced := List("2.12", "2.13", "3").map(_ -> "0.14.3").toMap
+    )
   )
 
 lazy val `circe-yaml` = project
@@ -70,8 +69,7 @@ lazy val `circe-yaml-v12` = project
       "org.scalacheck" %% "scalacheck" % Versions.scalaCheck % Test,
       "org.scalatest" %% "scalatest" % Versions.scalaTest % Test,
       "org.scalatestplus" %% "scalacheck-1-16" % Versions.scalaTestPlus % Test
-    ),
-    tlVersionIntroduced := List("2.12", "2.13", "3").map(_ -> "0.14.3").toMap
+    )
   )
 
 ThisBuild / developers := List(