update docker tag to 3.9.0 in documentation (#1060)

Author: kkloberdanz

extras/docker/README.md

@@ -16,6 +16,7 @@ is also known as
 
 ## Tags
 
+- [3.9.0-redhat-ubi-9.3](https://github.com/mongodb/mongo-cxx-driver/blob/ca6a89c3b4039b9b097a2945a2db1584d63a6b98/extras/docker/redhat-ubi-9.3/Dockerfile)
 - [3.8.1-redhat-ubi-9.2](https://github.com/mongodb/mongo-cxx-driver/blob/5b1b515e1b355943003d72a04ae47a9e0e174374/extras/docker/redhat-ubi-9.2/Dockerfile)
 - [3.8.0-redhat-ubi-9.2](https://github.com/mongodb/mongo-cxx-driver/blob/cb9dc3e927299bb9d2f2dc04878234e32c129685/extras/docker/redhat-ubi-9.2/Dockerfile)
 
@@ -31,7 +32,7 @@ instance for
 Next, create a `Dockerfile` like so.
 ```Dockerfile
 # Dockerfile
-FROM mongodb/mongo-cxx-driver:3.8.1-redhat-ubi-9.2
+FROM mongodb/mongo-cxx-driver:3.9.0-redhat-ubi-9.3
 
 WORKDIR /build
 
@@ -160,7 +161,7 @@ instance for
 Next, create a `Dockerfile` like so.
 ```Dockerfile
 # Dockerfile
-FROM mongodb/mongo-cxx-driver:3.8.1-redhat-ubi-9.2
+FROM mongodb/mongo-cxx-driver:3.9.0-redhat-ubi-9.3
 
 WORKDIR /build
 
@@ -316,4 +317,4 @@ Pinged your deployment using the MongoDB C Driver. You successfully connected to
 
 # License
 
-[Apache License Version 2.0](https://github.com/mongodb/mongo-cxx-driver/blob/master/LICENSE)
+[Apache License Version 2.0](https://github.com/mongodb/mongo-cxx-driver/blob/master/LICENSE)