dssp shoudn't include spdlog's bundled fmt.

[patlefort]

In dssp.cpp and structure.cpp, it should include fmt/printf.h instead. It create problems for packagers because spdlog is installed without a bundled fmt and it uses the system's fmt.

[yesint]

I've added fmt as an explicit dependency and dropped the usage of fmt bundled with spdlog. Please test.

[patlefort]

It's working, thank you.

[patlefort]

Another small aside: You should make your release tags annotated so that people can be notified via github.

[yesint]

Thank you for suggestion! This is an important point.