Update version string to prepare release 0.22.0 (#1556)

Author: yongtang

README.md

@@ -116,6 +116,7 @@ of releases [here](https://github.com/tensorflow/io/releases).
 
 | TensorFlow I/O Version | TensorFlow Compatibility | Release Date |
 | --- | --- | --- |
+| 0.22.0 | 2.7.x | Nov 10, 2021 |
 | 0.21.0 | 2.6.x | Sep 12, 2021 |
 | 0.20.0 | 2.6.x | Aug 11, 2021 |
 | 0.19.1 | 2.5.x | Jul 25, 2021 |

RELEASE.md

@@ -1,3 +1,20 @@
+# Release 0.22.0
+
+## Bug Fixes
+* Fix hdfs file system append error.
+* Add support for Azure Shared Access Signatures.
+* Fix several Azure file system related issues.
+* Update Dicom tutorial to include tag examples.
+
+## Thanks to our Contributors
+
+This release contains contributions from many people:
+
+Cheng Ren, Jan Bernlöhr, Vignesh Kothapalli, Yong Tang, Z_Wael
+
+We are also grateful to all who filed issues or helped resolve them, asked and
+answered questions, and were part of inspiring discussions.
+
 # Release 0.21.0
 
 ## Bug Fixes

tensorflow_io/python/ops/version_ops.py

@@ -14,5 +14,5 @@
 # ==============================================================================
 """version_ops"""
 
-version = "0.21.0"
+version = "0.22.0"
 require = "tensorflow>=2.7.0,<2.8.0"