fsverity-utils release notes

Version 1.5

Made the fsverity sign command and the libfsverity_sign_digest() function support PKCS#11 tokens.
Avoided a compiler error when building with musl libc.
Avoided compiler warnings when building with OpenSSL 3.0.
Improved documentation and test scripts.

Added a manual page for the fsverity utility.
Added the fsverity dump_metadata subcommand.
Added the --out-merkle-tree and --out-descriptor options to fsverity digest and fsverity sign.
Added metadata callbacks support to libfsverity_compute_digest().

Added a fsverity digest subcommand.
Added libfsverity_enable() and libfsverity_enable_with_sig().
Added basic support for Windows builds of fsverity using MinGW.
fsverity now defaults to 4096-byte blocks on all platforms.
libfsverity now will use SHA-256 with 4096-byte blocks if the hash_algorithm and block_size fields are left 0.
make install now installs a pkg-config file for libfsverity.
The Makefile now uses pkg-config to get the libcrypto build flags.
Fixed make check with USE_SHARED_LIB=1.

Split the file digest computation and signing functionality of the fsverity program into a library libfsverity. See README.md and Makefile for more details.
Improved the Makefile.
Added some tests. They can be run using make check. Also added scripts/run-tests.sh which does more extensive prerelease tests.
Lots of cleanups and other small improvements.