.github/workflows: update ronn to 0.9 (#483)

This fixes apostrophes in generated manpage.
Apostrophes should be entered as `'` ; using `\'` produces an acute accent.

ronn in Ubuntu is from https://github.com/apjanke/ronn-ng

.github/workflows/ronn.yml

@@ -6,7 +6,6 @@ on:
     paths:
       - '**.ronn'
       - '**/ronn.yml'
-      - '**/ronn/**'
 permissions:
   contents: read
 jobs:
@@ -16,9 +15,10 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v2
+      - name: Install ronn
+        run: sudo apt-get update && sudo apt-get install -y ronn
       - name: Run ronn
-        uses: ./.github/workflows/ronn
-        id: ronn
+        run: bash -O globstar -c 'ronn **/*.ronn'
       - name: Undo email mangling
         # rdiscount randomizes the output for no good reason, which causes
         # changes to always get committed. Sigh.

.github/workflows/ronn/Dockerfile

@@ -1,8 +0,0 @@
-FROM ruby:3.0.1-buster
-
-RUN apt-get update && apt-get install -y groff
-RUN bundle config --global frozen 1
-COPY Gemfile Gemfile.lock ./
-RUN bundle install
-ENTRYPOINT ["bash", "-O", "globstar", "-c", \
-    "/usr/local/bundle/bin/ronn **/*.ronn"]

.github/workflows/ronn/Gemfile

@@ -1,5 +0,0 @@
-# frozen_string_literal: true
-
-source "https://rubygems.org"
-
-gem "ronn", "~> 0.7.3"

.github/workflows/ronn/Gemfile.lock

@@ -1,20 +0,0 @@
-GEM
-  remote: https://rubygems.org/
-  specs:
-    hpricot (0.8.6)
-    mustache (1.1.1)
-    rdiscount (2.2.0.2)
-    ronn (0.7.3)
-      hpricot (>= 0.8.2)
-      mustache (>= 0.7.0)
-      rdiscount (>= 1.5.8)
-
-PLATFORMS
-  aarch64-linux
-  x86_64-linux
-
-DEPENDENCIES
-  ronn (~> 0.7.3)
-
-BUNDLED WITH
-   2.2.15

.github/workflows/ronn/action.yml

@@ -1,4 +0,0 @@
-name: Ronn
-runs:
-  using: docker
-  image: Dockerfile