Set TF 2.3 for nightly (#2061)

Author: bhack

README.md

@@ -71,7 +71,7 @@ what it was tested against.
 #### Python Op Compatibility Matrix
 | TensorFlow Addons | TensorFlow | Python  |
 |:----------------------- |:---|:---------- |
-| tfa-nightly | 2.2 | 3.5, 3.6, 3.7, 3.8 | 
+| tfa-nightly | 2.3 | 3.5, 3.6, 3.7, 3.8 | 
 | tensorflow-addons-0.10.0 | 2.2 |3.5, 3.6, 3.7, 3.8 |
 | tensorflow-addons-0.9.1 | 2.1, 2.2 |3.5, 3.6, 3.7 |
 | tensorflow-addons-0.8.3 | 2.1 |3.5, 3.6, 3.7 |
@@ -96,7 +96,7 @@ is compiled differently. A typical example of this would be `conda`-installed Te
 #### C++ Custom Op Compatibility Matrix
 | TensorFlow Addons | TensorFlow | Compiler  | cuDNN | CUDA | 
 |:----------------------- |:---- |:---------|:---------|:---------|
-| tfa-nightly | 2.2 | GCC 7.3.1 | 7.6 | 10.1 |
+| tfa-nightly | 2.3 | GCC 7.3.1 | 7.6 | 10.1 |
 | tensorflow-addons-0.10.0 | 2.2  | GCC 7.3.1 | 7.6 | 10.1 |
 | tensorflow-addons-0.9.1 | 2.1  | GCC 7.3.1 | 7.6 | 10.1 |
 | tensorflow-addons-0.8.3 | 2.1  | GCC 7.3.1 | 7.6 | 10.1 |