fix: add instructions how to set up dockercfg for public registries only

Add an additional example how the dockercfg file could look like if access to private registries is not required.
This was raised as a question before so adding this to help customers not have to figure out everything on their own.

Author: ivanstanev

README.md

@@ -38,6 +38,12 @@ Both of these items must be provided from a Kubernetes secret. The secret must b
 }
 ```
 
+If access to private registries is not needed, the `dockercfg.json` file contents should look like this:
+
+```json
+{}
+```
+
 2. Locate your Snyk Integration ID from the Snyk Integrations page (navigate to https://app.snyk.io/org/YOUR-ORGANIZATION-NAME/manage/integrations/kubernetes) and copy it.
 The Snyk Integration ID is a UUID and looks similar to the following:
 ```

snyk-monitor/README.md

@@ -33,6 +33,12 @@ Both of these items must be provided by a Kubernetes secret. The secret must be
 }
 ```
 
+If access to private registries is not needed, the `dockercfg.json` file contents should look like this:
+
+```json
+{}
+```
+
 2. Locate your Snyk Integration ID from the Snyk Integrations page (navigate to https://app.snyk.io/org/YOUR-ORGANIZATION-NAME/manage/integrations/kubernetes) and copy it. The Snyk Integration ID looks similar to the following:
 ```
 abcd1234-abcd-1234-abcd-1234abcd1234