rfc2: relax LGPL-3.0 requirement

Problem: apparently LGPL becomes viral in the golang environment
because static linking is the best practice there.

If we were to implement a golang binding for Flux, licensing it
as LGPL would defeat one of our stated goals:

* Facilitate the use of Flux and its programming interfaces by external
  projects such as applications, application runtimes, and tools, that are
  distributed under a wide variety of open source and commercial licenses.

Such a project would likely require a permissive license to be useful.
Therefore, relax the LGPL-3.0 REQUIRED language to RECOMMENDED.

Author: garlick

spec_2.rst

@@ -78,7 +78,7 @@ Collaboration Model for Flux Projects
 License for Flux Projects
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
--  Flux projects SHALL be licensed under the `GNU Lesser General Public License (LGPL) version 3 <https://www.gnu.org/licenses/lgpl-3.0.en.html>`__.
+-  Flux projects are RECOMMENDED to be licensed under the `GNU Lesser General Public License (LGPL) version 3 <https://www.gnu.org/licenses/lgpl-3.0.en.html>`__.
 
 -  Flux projects are RECOMMENDED to permit redistribution and/or modification
    under the project’s base license version, or any later version per