update docu for custom extra hedaers in cmemc

Author: louiswesterheide

docs/automate/cmemc-command-line-interface/configuration/file-based-configuration/index.md

@@ -269,3 +269,12 @@ Setting this to a PEM file allows for using private Certificate Authorities for
 Please refer to [Certificate handling and SSL verification](../certificate-handling-and-ssl-verification/index.md) for more information.
 
 This variable defaults to `$PYTHON_HOME/site-packages/certifi/cacert.pem`.
+
+
+#### CMEMC_CUSTOM_HEADER_*
+
+Setting this allows all http requests cmemc does to use the specified custom headers as well.
+
+The `CMEMC_CUSTOM_HEADER_` prefix gets stripped from the header, so only `*` will remain.
+
+This variable defaults to `none`

docs/automate/cmemc-command-line-interface/configuration/getting-credentials-from-external-processes/index.md

@@ -60,6 +60,7 @@ In order to get credential information from an external process you need to use
 - `OAUTH_PASSWORD_PROCESS`, to set up the process to get the user password when using the `password` grant type.
 - `OAUTH_CLIENT_SECRET_PROCESS`, to set up the process to get the client secret when using `client_credentials` grant type .
 - `OAUTH_ACCESS_TOKEN_PROCESS`, to set up the process to get the direct access token (`prefetched_token`).
+- `CMEMC_CUSTOM_HEADER_*_PROCESS` to set up the process to get custom http headers if needed (the `*` needs to be replaced with the correct header name using all uppercase and `_` instead of `-`, e.g. `CMEMC_CUSTOM_HEADER_CF_ACCESS_TOKEN_PROCESS` for the `cf-access-token` header variable)
 
 The credential executable can use the other cmemc environment keys of the configuration block for fetching the credentials (e.g. `CMEM_BASE_URI` and `OAUTH_USER`).
 
@@ -87,6 +88,7 @@ OAUTH_CLIENT_ID=cmem-service-account
 OAUTH_CLIENT_SECRET_PROCESS=["getpass.sh", "parameter1", "parameter2"]
 ```
 
+Note: You need to define a named connection for this to take effect. Using the `[DEFAULT]` section fallback will not execute the process.
 ### Example: MacOS Keychain
 
 Here is a working example with the MacOS Keychain, which can be queried with the command line tool `security`.