Update tensorflow requirement

Updates the requirements on [tensorflow](https://github.com/tensorflow/tensorflow) to permit the latest version.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.2.0...v2.18.0)

---
updated-dependencies:
- dependency-name: tensorflow
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

setup.py

@@ -19,7 +19,7 @@ def readme():
     # https://github.com/SeldonIO/alibi-detect/issues/375 and 387
     "tensorflow": [
         "tensorflow_probability>=0.8.0, <0.23.0",
-        "tensorflow>=2.2.0, !=2.6.0, !=2.6.1, <2.15.0",  # https://github.com/SeldonIO/alibi-detect/issues/375 and 387
+        "tensorflow>=2.2.0, !=2.6.0, !=2.6.1, <2.19.0",  # https://github.com/SeldonIO/alibi-detect/issues/375 and 387
     ],
     "keops": [
         "pykeops>=2.0.0, <2.3.0",
@@ -28,7 +28,7 @@ def readme():
     "all": [
         "prophet>=1.1.0, <2.0.0",
         "tensorflow_probability>=0.8.0, <0.23.0",
-        "tensorflow>=2.2.0, !=2.6.0, !=2.6.1, <2.15.0",  # https://github.com/SeldonIO/alibi-detect/issues/375 and 387
+        "tensorflow>=2.2.0, !=2.6.0, !=2.6.1, <2.19.0",  # https://github.com/SeldonIO/alibi-detect/issues/375 and 387
         "pykeops>=2.0.0, <2.3.0",
         "torch>=1.7.0, <3.0.0"
     ],