Update Jekyll

Also, remove unused jekyll-pwa-plugin - don't think we will ever use this.

Author: philwareham

Gemfile

@@ -1,10 +1,9 @@
 source "https://rubygems.org"
 
-gem "jekyll", "4.2.1"
+gem "jekyll", "4.3.1"
 
 group :jekyll_plugins do
-  gem "jekyll-feed", "0.16.0"
-  gem "jekyll-pwa-plugin", "5.1.5"
-  gem "jekyll-seo-tag", "2.7.1"
+  gem "jekyll-feed", "0.17.0"
+  gem "jekyll-seo-tag", "2.8.0"
   gem "jekyll-sitemap", "1.4.0"
 end

_config.yml

@@ -3,7 +3,6 @@ timezone: Europe/London
 permalink: /:categories/:title
 plugins:
   - jekyll-feed
-  - jekyll-pwa-plugin
   - jekyll-seo-tag
   - jekyll-sitemap
 author: The Textpattern Development Team and contributors
@@ -21,16 +20,3 @@ highlighter: none
 keep_files: [
   'expect-ct-report'
 ]
-pwa: # See https://github.com/lavas-project/jekyll-pwa
-  enabled: false # Optional
-  sw_src_filepath: service-worker.js # Optional
-  sw_dest_filename: service-worker.js # Optional
-  dest_js_directory: assets/js # Required
-  precache_recent_posts_num: 5 # Optional
-  precache_glob_directory: / # Optional
-  precache_glob_patterns: # Optional
-    - "{js,css,fonts}/**/*.{js,css,eot,svg,ttf,woff}"
-    - index.html
-  precache_glob_ignores: # Optional
-    - sw-register.js
-    - "fonts/**/*"