fix nokogiri & mdbook installs (#62)

* upgrade nokogiri

we're running into the issue fixed in sparklemotion/nokogiri#2106

* build mdbook without search feature

error is:

error: failed to compile `mdbook v0.2.3`, intermediate artifacts can be found at `/tmp/cargo-installjZOKMC`

Caused by:
  failed to select a version for the requirement `ammonia = "^1.1"`
  candidate versions found which didn't match: 3.3.0, 3.2.1, 3.2.0, ...

I believe because ammonia-1.1 was pulled from crates.io

.github/workflows/main.yml

@@ -21,7 +21,7 @@ jobs:
     - name: Install Rust
       run: rustup update stable && rustup default stable
     - run: gem install bundler -v 1.16.5 && bundle install --retry=3 --jobs=4
-    - run: cargo install mdbook --version 0.2.3
+    - run: cargo install mdbook --version 0.2.3 --no-default-features
     - run: ./ci/build.sh
 
     - name: Push to gh-pages

Gemfile

@@ -28,3 +28,5 @@ gem "tzinfo-data", platforms: [:mingw, :mswin, :x64_mingw, :jruby]
 # Performance-booster for watching directories on Windows
 gem "wdm", "~> 0.1.0" if Gem.win_platform?
 gem "github-pages", group: :jekyll_plugins
+
+gem "nokogiri", "~> 1.11"

Gemfile.lock

@@ -198,20 +198,22 @@ GEM
       rb-inotify (~> 0.9, >= 0.9.7)
       ruby_dep (~> 1.2)
     mercenary (0.3.6)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.8.5)
     minima (2.5.0)
       jekyll (~> 3.5)
       jekyll-feed (~> 0.9)
       jekyll-seo-tag (~> 2.1)
     minitest (5.11.3)
     multipart-post (2.0.0)
-    nokogiri (1.10.1)
-      mini_portile2 (~> 2.4.0)
+    nokogiri (1.15.5)
+      mini_portile2 (~> 2.8.2)
+      racc (~> 1.4)
     octokit (4.13.0)
       sawyer (~> 0.8.0, >= 0.5.3)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (3.0.3)
+    racc (1.7.3)
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)
       ffi (~> 1.0)
@@ -246,6 +248,7 @@ DEPENDENCIES
   jekyll (~> 3.7.3)
   jekyll-feed (~> 0.6)
   minima (~> 2.0)
+  nokogiri (~> 1.11)
   tzinfo-data
 
 BUNDLED WITH