nimble: remove -s flag from strip command

With Zig 0.10.0 (2022-10-31), `zig cc` now properly uses the `--passL:
-s` option that we use in `config.nims`. So we can remove the `-s` flag
from our post-build hook.

From the Zig 0.10.0 release notes [1]:

    `zig cc` is Zig's drop-in C compiler tool. Enhancements in this release:

    [...]
    - Integration with more linker args:

      - `--whole-archive`, `-whole-archive`
      - `--no-whole-archive`, `-no-whole-archive`
      - `-s`, `--strip-all`
      - `-S`, `--strip-debug`
    [...]

[1] https://ziglang.org/download/0.10.0/release-notes.html#zig-cc

configlet.nimble

@@ -45,4 +45,4 @@ when defined(linux):
     if existsEnv("GITHUB_ACTIONS") and findExe("zigcc").len > 0:
       exec "readelf -p .comment ./configlet"
       echo "stripping binary..."
-      exec "strip -s -R .comment ./configlet"
+      exec "strip -R .comment ./configlet"