Update upstream BD/B/CB/S

Note to other developers: This commit may require you to wipe your
workspace as a result of the changes to BD.

--- work/BuildData
Submodule work/BuildData f527a8ff..d56672db:
  > Mappings Update

--- work/Bukkit
Submodule work/Bukkit 0c1d258bb..db06c80d7:
  > Add list of entities to EntityTransformEvent
  > SPIGOT-4347: Add API to allow storing arbitrary values on ItemStacks

---work/CraftBukkit
Submodule work/CraftBukkit 6a398ac44..068dab5be:
  > Enable optional source JAR shading via profile shadeSourcesJar
  > Use ImmutableList rather than AbstractList for CraftMetaBook
  > Fix setRecipes(List) not setting Knowledge Book recipes.
  > Mappings Update
  > Add list of entities to EntityTransformEvent & move die calls
  > SPIGOT-4347: Add API to allow storing arbitrary values on ItemStacks
  > Add Vanilla help to default permissions

--- work/Spigot
Submodule work/Spigot a1f2566f6..e769fe4d9:
  > Mappings Update
  > Rebuild patches

Spigot-Server-Patches/POM-Changes.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] POM Changes
 
 
 diff --git a/pom.xml b/pom.xml
-index 7ac07ac07ac0..7ac07ac07ac0 100644
+index ccf92b011..f0fc37abf 100644
 --- a/pom.xml
 +++ b/pom.xml
 @@ -0,0 +0,0 @@
@@ -111,6 +111,7 @@ index 7ac07ac07ac0..7ac07ac07ac0 100644
                          </goals>
                          <configuration>
 +                            <dependencyReducedPomLocation>${project.build.directory}/dependency-reduced-pom.xml</dependencyReducedPomLocation> <!-- Paper -->
+                             <createSourcesJar>${shadeSourcesJar}</createSourcesJar>
                              <relocations>
 -                                <relocation>
 -                                    <pattern>joptsimple</pattern>
@@ -157,7 +158,7 @@ index 7ac07ac07ac0..7ac07ac07ac0 100644
              <plugin>
                  <groupId>org.apache.maven.plugins</groupId>
 diff --git a/src/main/java/org/bukkit/craftbukkit/util/Versioning.java b/src/main/java/org/bukkit/craftbukkit/util/Versioning.java
-index 7ac07ac07ac0..7ac07ac07ac0 100644
+index 93046379d..674096cab 100644
 --- a/src/main/java/org/bukkit/craftbukkit/util/Versioning.java
 +++ b/src/main/java/org/bukkit/craftbukkit/util/Versioning.java
 @@ -0,0 +0,0 @@ public final class Versioning {