Release 0.6 (#452)

* Version 0.6.0

* Update changelog with release date
diff --git a/Cargo.toml b/Cargo.toml
index 2c8bb7f..eb39305 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 
 name = "petgraph"
-version = "0.5.1"
+version = "0.6.0"
 readme = "README.rst"
 license = "MIT/Apache-2.0"
 authors = [
diff --git a/RELEASES.rst b/RELEASES.rst
index ce3dddb..5f6cb6d 100644
--- a/RELEASES.rst
+++ b/RELEASES.rst
@@ -1,4 +1,4 @@
-Version 0.6.0 (2021-07-XX)
+Version 0.6.0 (2021-07-04)
 ==========================
 
 Breaking changes
@@ -91,6 +91,7 @@
 .. _`#437`: https://github.com/petgraph/petgraph/issues/437
 .. _`#440`: https://github.com/petgraph/petgraph/issues/440
 .. _`#443`: https://github.com/petgraph/petgraph/issues/443
+.. _`#444`: https://github.com/petgraph/petgraph/issues/444
 .. _`#449`: https://github.com/petgraph/petgraph/issues/449
 .. _`#450`: https://github.com/petgraph/petgraph/issues/450