util/util-slf4j-api: scala3 migration

**Problem**
We're migrating util-slf4j-api to scala3. Dotty has new syntax rules that need
to be addressed. This project also depends on util-mock and therefore on
mockito-scala, which is incompatible with scala3.

**Solution**
Use migration flags to solve syntax warnings. Remove dependency on mockito-scala
and use mockito-core instead in LoggingTest and MarkerLoggingTest.

JIRA Issues: CSL-11110

Differential Revision: https://phabricator.twitter.biz/D725491

Author: Natalia Margarita Gonzalez Herrera

CHANGELOG.rst

@@ -6,13 +6,14 @@ Note that ``PHAB_ID=#`` and ``RB_ID=#`` correspond to associated messages in com
 
 Unreleased
 ----------
+* util-sl4j-api: Experimentally crossbuilds with Scala 3. ``PHAB_ID=D725491``
+
 * util-cache-guava: Experimentally crossbuilds with Scala 3. ``PHAB_ID=D716101``.
 
 * util-cache: Experimentally crossbuilds with Scala 3. ``PHAB_ID=D714304``.
 
 New Features
 ~~~~~~~~~~~~
-
 * util-zk-test: Experimentally crossbuilds with Scala 3. ``PHAB_ID=D720603``
 
 21.8.0 (No 21.7.0 Release)

build.sbt

@@ -583,15 +583,15 @@ lazy val utilSlf4jApi = Project(
   id = "util-slf4j-api",
   base = file("util-slf4j-api")
 ).settings(
-    sharedSettings
+    sharedScala3EnabledSettings
   ).settings(
     name := "util-slf4j-api",
     libraryDependencies ++= Seq(
       slf4jApi,
-      "org.mockito" %% "mockito-scala" % mockitoScalaVersion % "test",
-      "org.slf4j" % "slf4j-simple" % slf4jVersion % "test"
-    )
-  ).dependsOn(utilCore % "test", utilMock % "test")
+      "org.mockito" % "mockito-core" % mockitoVersion % "test",
+      "org.slf4j" % "slf4j-simple" % slf4jVersion % "test",
+    ) ++ scalatestMockitoVersionedDep(scalaVersion.value)
+  ).dependsOn(utilCore % "test")
 
 lazy val utilSlf4jJulBridge = Project(
   id = "util-slf4j-jul-bridge",

util-slf4j-api/src/test/scala/com/twitter/util/logging/BUILD

@@ -7,6 +7,11 @@ scala_library(
     ],
     tags = ["bazel-compatible"],
     dependencies = [
+        "3rdparty/jvm/org/mockito:mockito-core",
+        "3rdparty/jvm/org/scalatest",
+        "3rdparty/jvm/org/scalatestplus:junit",
+        "3rdparty/jvm/org/scalatestplus:mockito-3-3",
+        "3rdparty/jvm/org/scalatestplus:scalacheck",
         "3rdparty/jvm/org/slf4j:slf4j-api",
         "util/util-core/src/main/scala/com/twitter/io",
         "util/util-slf4j-api/src/main/scala/com/twitter/util/logging",