tex-babel-russian: update to 1.3m

2021-01-10 version 1.3m

    * The macro `\cyrdash` that prints Cyrillic dash has been changed.
      Now it is alias of `\textemdash` in all encodings.

    * New Customisation section added to the module documentation. It
      describes how to modify the `\cyrdash` macro and shorthand
      `"--~"` that is intended to print Cyrillic dash in compound names
      of physical laws, mathematical equations, company titles, e.t.c.
      such as the Ostrogradsky-Gauss theorem (thanks to Olga Lapko).

2020-10-16 version 1.3l

    * Patches for Russian language from hyperref package to
      babel-russian module (thanks to Ulrike Fischer).

(markd)