Update guacamole/guacamole Docker tag to v1.4.0

This MR contains the following updates:

Package	Type	Update	Change
guacamole/guacamole	ironbank-docker	minor	1.3.0 -> 1.4.0
guacamole/guacamole		minor	1.3.0 -> 1.4.0
guacamole/guacamole	stage	minor	1.3.0 -> 1.4.0

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