Hello !
I found error as shown in #133
I tried to fix this by using windows as system.
Cache was made but the new error occured.

Run actions/cache@v1
Cache Size: ~102 MB (107455822 B)
C:\windows\System32\tar.exe -xz -f d:\a_temp\5bff5da6-b2e7-439a-9f1e-b8eb52fb391e\cache.tgz -C C:\Users\runneradmin.cargo\registry
./index/github.com-1ecc6299db9ec823/.git/objects/pack/pack-a1b8e2d02676504008fea86ca360367fcee5bd43.idx: Can't unlink already-existing object
./index/github.com-1ecc6299db9ec823/.git/objects/pack/pack-a1b8e2d02676504008fea86ca360367fcee5bd43.pack: Can't unlink already-existing object
tar.exe: Error exit delayed from previous errors.
[warning]Tar failed with error: The process 'C:\windows\System32\tar.exe' failed with exit code 1. Ensure BSD tar is installed and on the PATH.

I am trying to cache cargo. I am using code from Action examples