Merge branch 'patch-1' into 'master'

Fix Incorrect Quote In Docker Executor Example

## What does this MR do?
The corrected line opened with a regular quote (') but closed with a back-tick (`)  
I believe this is invalid bash syntax

## Are there points in the code the reviewer needs to double check?
Probably not

## Why was this MR needed?
Fixes error when example is copied and pasted

## What are the relevant issue numbers?
None

## Screenshots (if relevant)
None

See merge request !3604

doc/ci/ssh_keys/README.md

@@ -57,7 +57,7 @@ before_script:
   # WARNING: Use this only with the Docker executor, if you use it with shell
   # you will overwrite your user's SSH config.
   - mkdir -p ~/.ssh
-  - '[[ -f /.dockerinit ]] && echo -e "Host *\n\tStrictHostKeyChecking no\n\n" > ~/.ssh/config`
+  - '[[ -f /.dockerinit ]] && echo -e "Host *\n\tStrictHostKeyChecking no\n\n" > ~/.ssh/config'
 ```
 
 As a final step, add the _public_ key from the one you created earlier to the