Enable IP anonymization in Google Analytics (GDPR)

- Introduced "ga_tracking_anonymize_ip" parameter to enable/disable Google Analytics IP anonymization (to comply with GDPR).

(cherry picked from commit ce530f36fa0549c78ffe53ea6077f44f6f0b330f) (+1 squashed commit)
Squashed commits:
[69b7718] - enable GA anonymize_ip

(cherry picked from commit f2b67c632af72b61dd634b9a337200781519691e)

_config.yml

@@ -47,6 +47,7 @@ color_scheme: nil
 # Google Analytics Tracking (optional)
 # e.g, UA-1234567-89
 ga_tracking: UA-2709176-10
+ga_tracking_anonymize_ip: true
 
 plugins:
   - jekyll-seo-tag

_includes/head.html

@@ -21,7 +21,7 @@
       function gtag(){dataLayer.push(arguments);}
       gtag('js', new Date());
 
-      gtag('config', "{{ site.ga_tracking }}");
+      gtag('config', '{{ site.ga_tracking }}'{% if site.ga_tracking_anonymize_ip %}, { 'anonymize_ip': true }{% endif %});
     </script>
 
   {% endif %}

docs/configuration.md

@@ -85,4 +85,5 @@ See [Customization]({{ site.baseurl }}{% link docs/customization.md %}) for more
 # Google Analytics Tracking (optional)
 # e.g, UA-1234567-89
 ga_tracking: UA-5555555-55
+ga_tracking_anonymize_ip: true
 ```