Bump grpcio from 1.18.0 to 1.53.0

Bumps [grpcio](https://github.com/grpc/grpc) from 1.18.0 to 1.53.0.
- [Release notes](https://github.com/grpc/grpc/releases)
- [Changelog](https://github.com/grpc/grpc/blob/master/doc/grpc_release_schedule.md)
- [Commits](grpc/grpc@v1.18.0...v1.53.0)

---
updated-dependencies:
- dependency-name: grpcio
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,2 +1,2 @@
-grpcio==1.18.0
+grpcio==1.53.0
 protobuf==3.15.0

setup.py

@@ -10,7 +10,7 @@
       licencse='Apache 2.0',
       packages=['iosxr_grpc'],
       install_requires=[
-          'grpcio==1.18.0',
+          'grpcio==1.53.0',
           'protobuf==3.15.0',
       ],
       zip_safe=False)