`poetry update <package>` does not work properly with optional git packages

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Windows 10
• Poetry version: ^1.2.0
• Link of a Gist with the contents of your pyproject.toml file: here

Issue

I wanted to update the optional Git dependency ruwiktionary-html-parser. To do this, I executed `poetry update --only "database-creation" to only the database-creation dependencies (where the dependency I wanted to update is included).

Now, when I run poetry show -v I get the displayed package version as ruwiktionary-htmldump-parser 0.1.4 c649ece. However, when I follow the link to the venv and look at the installed packages, I find the file ruwiktionary_htmldump_parser-0.1.2.dist-info and notice that the code is also not up to date. The update command only seems to have change the displayed version, but did not actually install anything.

Start with the linked pyproject.toml and reproduce the update using the database-creation group on Windows 10 with Poetry ^1.2.0. Compare poetry show -v with the installed virtual-environment dist-info and package code; done means the optional Git dependency is actually installed at the selected revision rather than only showing an updated version.