chore: add support for 2.12.18 (#550)

closes #548

Author: ckipp01

.github/workflows/ci.yml

@@ -19,9 +19,9 @@ jobs:
         os: [ 'ubuntu-latest', 'windows-latest' ]
         java: ['8', '17']
         scala: [
+            { version: '2.12.18' },
             { version: '2.12.17' },
             { version: '2.12.16' },
-            { version: '2.12.15' },
             { version: '2.13.10' },
             { version: '2.13.9' },
             { version: '2.13.8' },

build.sbt

@@ -2,13 +2,14 @@ import sbtcrossproject.CrossProject
 import sbtcrossproject.CrossType
 
 lazy val munitVersion = "0.7.29"
-lazy val scalametaVersion = "4.6.0"
-lazy val defaultScala212 = "2.12.17"
+lazy val scalametaVersion = "4.7.8"
+lazy val defaultScala212 = "2.12.18"
 lazy val defaultScala213 = "2.13.10"
 lazy val defaultScala3 = "3.3.0"
 lazy val bin212 =
   Seq(
     defaultScala212,
+    "2.12.17",
     "2.12.16",
     "2.12.15",
     "2.12.14",