meson: add a missing versiondep to libcryptsetup-plugins target

Otherwise the build sometimes fails in a racy way:

```
[274/1850] Compiling C object src/cryptsetup/cryptsetup-tokens/libcryptsetup-token-systemd-tpm2_static.a.p/cryptsetup-token-systemd-tpm2.c.o
FAILED: src/cryptsetup/cryptsetup-tokens/libcryptsetup-token-systemd-tpm2_static.a.p/cryptsetup-token-systemd-tpm2.c.o
cc -Isrc/cryptsetup/cryptsetup-tokens/libcryptsetup-token-systemd-tpm2_static.a.p (...) -c ../build/src/cryptsetup/cryptsetup-tokens/cryptsetup-token-systemd-tpm2.c
../build/src/cryptsetup/cryptsetup-tokens/cryptsetup-token-systemd-tpm2.c:12:10: fatal error: version.h: No such file or directory
   12 | #include "version.h"
         |          ^~~~~~~~~~~
         compilation terminated.
```

Follow-up to d1ae38d8.