Update bash to use "%%IMAGE%%"

bash/content.md

@@ -21,7 +21,7 @@ There are a few main things that are important to note regarding this image:
 ## Interactive shell
 
 ```console
-$ docker run -it --rm bash:4.4
+$ docker run -it --rm %%IMAGE%%:4.4
 bash-4.4# which bash
 /usr/local/bin/bash
 bash-4.4# echo $BASH_VERSION
@@ -31,16 +31,16 @@ bash-4.4# echo $BASH_VERSION
 ## Testing scripts via bind-mount
 
 ```console
-$ docker run -it --rm -v /path/to/script.sh:/script.sh:ro bash:4.4 bash /script.sh
+$ docker run -it --rm -v /path/to/script.sh:/script.sh:ro %%IMAGE%%:4.4 bash /script.sh
 ...
-$ docker run -it --rm -v /path/to/script.sh:/script.sh:ro bash:3.2 bash /script.sh
+$ docker run -it --rm -v /path/to/script.sh:/script.sh:ro %%IMAGE%%:3.2 bash /script.sh
 ...
 ```
 
 ## Testing scripts via `Dockerfile`
 
 ```dockerfile
-FROM bash:4.4
+FROM %%IMAGE%%:4.4
 
 COPY script.sh /