finish dropping Scala.js 0.6.x support

Author: SethTisue

.travis.yml

@@ -12,20 +12,11 @@ scala:
 
 env:
   - SCALAJS_VERSION=       ADOPTOPENJDK=8
-  - SCALAJS_VERSION=0.6.33 ADOPTOPENJDK=8
   - SCALAJS_VERSION=1.3.1  ADOPTOPENJDK=8
   - SCALAJS_VERSION=       ADOPTOPENJDK=11
-  - SCALAJS_VERSION=0.6.33 ADOPTOPENJDK=11
   - SCALAJS_VERSION=1.3.1  ADOPTOPENJDK=11
 
 matrix:
-  exclude:
-    # Scala.js 0.6.x is not supported with Scala 3
-    - scala: 3.0.0-M1
-      env: SCALAJS_VERSION=0.6.33 ADOPTOPENJDK=8
-
-    - scala: 3.0.0-M1
-      env: SCALAJS_VERSION=0.6.33 ADOPTOPENJDK=11
 
   include:
 

compat/src/test/scala/test/scala/collection/LazyListLazinessTest.scala

@@ -825,7 +825,6 @@ class LazyListLazinessTest {
   }
 
   @Test
-  @Ignore // TODO: enable after we drop Scala.js 0.6.x support
   def `#::_properlyLazy`(): Unit = {
     // genericCons_properlyLazy(_ #:: _)
     genericCons_properlyLazy((hd, tl) => tl.#::(hd))