keyring update from CRAN

[gaborcsardi]

Version: 1.3.1
Check: whether package can be installed
Result: WARN 
  Found the following significant warnings:
    keyring_secret_service.c:188:23: warning: format string is not a string literal (potentially insecure) [-Wformat-security]
    keyring_secret_service.c:351:23: warning: format string is not a string literal (potentially insecure) [-Wformat-security]
  See ‘/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/keyring.Rcheck/00install.out’ for details.
  * used C compiler: ‘Debian clang version 17.0.5 (1)’
Flavor: [r-devel-linux-x86_64-debian-clang](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-debian-clang/keyring-00check.html)

Version: 1.3.1
Check: Rd \usage sections
Result: NOTE 
  Documented arguments not in \usage in Rd file 'b_wincred_get.Rd':
    ‘backend’
  
  Functions with \usage entries need to have the appropriate \alias
  entries, and all their arguments documented.
  The \usage entries must correspond to syntactically valid R code.
  See chapter ‘Writing R documentation files’ in the ‘Writing R
  Extensions’ manual.
Flavors: [r-devel-linux-x86_64-debian-clang](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-debian-clang/keyring-00check.html), [r-devel-linux-x86_64-debian-gcc](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-debian-gcc/keyring-00check.html), [r-devel-linux-x86_64-fedora-clang](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-fedora-clang/keyring-00check.html), [r-devel-linux-x86_64-fedora-gcc](https://www.r-project.org/nosvn/R.check/r-devel-linux-x86_64-fedora-gcc/keyring-00check.html), [r-devel-windows-x86_64](https://www.r-project.org/nosvn/R.check/r-devel-windows-x86_64/keyring-00check.html)

[gaborcsardi]

Closed in #146.