docs(rtd): fix migration section (#2289)

The new sections were not uploaded from GH actions to RTD, do so. Also move the PRT mf6.5->6.6 migration guide from the src/ to the .build_rtd_docs/ folder so it doesn't show up in the API docs.

Author: wpbonelli

.build_rtd_docs/conf.py

@@ -98,9 +98,9 @@
 
 print(f"Copy migration guides to {dstdir}")
 fpth = "mf6_6_0_prt_migration_guide.md"
-src = os.path.join("..", "src", "Solution", "ParticleTracker", fpth)
+src = os.path.join(fpth)
 dst = os.path.join(dstdir, fpth)
-shutil.copy(src, dst)
+shutil.move(src, dst)
 
 # -- build the deprecations table --------------------------------------------
 print("Build the deprecations markdown table")

src/Solution/ParticleTracker/mf6_6_0_prt_migration_guide.md renamed to .build_rtd_docs/mf6_6_0_prt_migration_guide.md

@@ -174,9 +174,11 @@ jobs:
           name: rtd-files-for-${{ github.sha }}
           path: |
             modflow6/.build_rtd_docs/dev.rst
+            modflow6/.build_rtd_docs/migration.rst
             modflow6/.build_rtd_docs/index.rst
             modflow6/.build_rtd_docs/mf6io.rst
             modflow6/.build_rtd_docs/_dev/
+            modflow6/.build_rtd_docs/_migration/
             modflow6/.build_rtd_docs/_mf6io/
             modflow6/.build_rtd_docs/_mf6run/
             modflow6/.build_rtd_docs/_static/