ci: revert merge of nightly branch

The nightly branch is required because the GHA CI doesn't actually do
the build, and snapcraft requires it to be like this.

snapcraft consumes each branch and runs the `snapcraft.yaml`.

.github/workflows/update-readme.yaml

@@ -6,7 +6,8 @@ on:
     - cron: '45 11 * * *'
 
 jobs:
-  update_readme:
+  # Updates the timestamp in README.md, which triggers a "push" event.
+  bump_timestamp:
     permissions:
       contents: write
     runs-on: ubuntu-latest

snap/snapcraft.yaml

@@ -32,28 +32,17 @@ apps:
     desktop: usr/share/applications/nvim.desktop
 
 parts:
-  name: publish ${{ matrix.nvimbranch }}
-  strategy:
-    fail-fast: false
-    matrix:
-      nvimbranch: [ stable, nightly ]
   nvim:
     source: https://github.com/neovim/neovim.git
     override-pull: |
       craftctl default
-      branch="${{ matrix.nvimbranch }}"
+      branch="stable"
       git checkout tags/${branch} -b ${branch}
       major="$(awk '/NVIM_VERSION_MAJOR/{gsub(")","",$2); print $2}' CMakeLists.txt)"
       minor="$(awk '/NVIM_VERSION_MINOR/{gsub(")","",$2); print $2}' CMakeLists.txt)"
       patch="$(awk '/NVIM_VERSION_PATCH/{gsub(")","",$2); print $2}' CMakeLists.txt)"
-      if [ stable = "${{ matrix.nvimbranch }}" ] ; then
-        version="v$major.$minor.$patch"
-        craftctl set version="${version}"
-      else
-        version_prefix="v$major.$minor.$patch"
-        git_described="$(git describe --first-parent 2> /dev/null | perl -lpe 's/v\d.\d.\d-//g' | perl -lpe 's/-/+/g')"
-        craftctl set version="${version_prefix}-${git_described}"
-      fi
+      version="v$major.$minor.$patch"
+      craftctl set version="${version}"
     plugin: make
     override-build: |
       echo "Building on $SNAP_ARCH"