create tag with message results in fatal error if username contains space

What steps will reproduce the problem?

1. TortoiseGit --> Create Tag
2. enter a Tag name and a message
3. press okay
4. Error message: "fatal: could not open or read 'C:\Users\thomas': Permission denied

What is the expected output? What do you see instead?

creating a tag should work also when adding a message.

What version of TortoiseGit and Git are you using? On what operating system?

• TortoiseGit-2.7.0-64bit.msi and TortoiseGit-preview-2.7.7.0-20190214-b336bafe-64bit.msi
• Windows 10 1809

Please provide any additional information below.

When you don't add a message when creating a tag it's working fine. I have a space in my Windows username "thomas kais". I sign all my commits with GPG. Normal commits work fine without any issues. Only while creating a tag with a message I'll get this error.