Update to mmtk 0.3.0 (#57)

Author: qinsoon

mmtk/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mmtk_openjdk"
-version = "0.2.0"
+version = "0.3.0"
 authors = [" <>"]
 
 [lib]
@@ -21,7 +21,7 @@ lazy_static = "1.1"
 # - change branch
 # - change repo name
 # But other changes including adding/removing whitespaces in commented lines may break the CI.
-mmtk = { git = "ssh://[email protected]/mmtk/mmtk-core.git", rev = "9f9e3c615858eb5dcf4f66be822a1e3598b2448f" }
+mmtk = { git = "ssh://[email protected]/mmtk/mmtk-core.git", rev = "141639ab452cc464b8a41f55356e9dc945066b1a" }
 # Uncomment the following to build locally
 # mmtk = { path = "../repos/mmtk-core" }