bump sbt-protoc for better integration with common-protos

Fixes scripted 10-scalapb-validate, see
* scalapb/ScalaPB#873 (comment)
* scalapb/scalapb-validate#70

Other changes
* cacheClassLoaders is now deprecated, see
  thesamet/sbt-protoc@2a730a4
* Forcing recompilation is no longer necessary as the cache gets
  invalidated if a sandbox genererator classpath is updated, see
  thesamet/sbt-protoc@80824b0
* The new classloader caching implementation resolves sandboxed
  generators artifacts earlier, even if they are no sources. That is
  the case for Test / protocGenerate, which was starting before
  codeGenProject / Compile / publishLocal, causing:
  > Error downloading com.lightbend.akka.grpc:akka-grpc-codegen_2.12:
  > 1.1.0-5-c5975cd5

benchmark-java/build.sbt

@@ -29,7 +29,7 @@ val root = project.in(file("."))
       "org.scalatest" %% "scalatest" % "3.1.2" % "test",
       "org.scalatestplus" %% "junit-4-12" % "3.1.2.0" % "test"
     ),
-    Compile / PB.generate := ((Compile / PB.generate) dependsOn (
+    PB.artifactResolver := (PB.artifactResolver dependsOn (
         codeGenProject / Compile / publishLocal)).value
   )
 

project/ReflectiveCodeGen.scala

@@ -64,8 +64,6 @@ object ReflectiveCodeGen extends AutoPlugin {
             }
           }
         }.value,
-        // Reload generators on each invocation
-        PB.cacheClassLoaders := false,
         setCodeGenerator := loadAndSetGenerator(
           // the magic sauce: use the output classpath from the the sbt-plugin project and instantiate generators from there
           (fullClasspath in Compile in ProjectRef(file("."), "sbt-akka-grpc")).value,
@@ -76,7 +74,6 @@ object ReflectiveCodeGen extends AutoPlugin {
           codeGeneratorSettings.value,
           PB.targets.value.asInstanceOf[ListBuffer[Target]],
           scalaBinaryVersion.value),
-        PB.recompile ~= (_ => true),
         PB.protoSources in Compile := PB.protoSources.value ++ Seq(
           PB.externalIncludePath.value,
           sourceDirectory.value / "proto"))) ++ Seq(

project/plugins.sbt

@@ -1,6 +1,6 @@
 enablePlugins(BuildInfoPlugin)
 
-val sbtProtocV = "1.0.0"
+val sbtProtocV = "1.0.1"
 
 buildInfoKeys := Seq[BuildInfoKey]("sbtProtocVersion" -> sbtProtocV)