Bump pg_search from 1.0.6 to 2.1.2

Bumps [pg_search](https://github.com/Casecommons/pg_search) from 1.0.6 to 2.1.2.
- [Release notes](https://github.com/Casecommons/pg_search/releases)
- [Changelog](https://github.com/Casecommons/pg_search/blob/master/CHANGELOG.md)
- [Commits](Casecommons/pg_search@v1.0.6...v2.1.2)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Gemfile.lock

@@ -229,7 +229,7 @@ GEM
     http-cookie (1.0.3)
       domain_name (~> 0.5)
     httpclient (2.8.2.4)
-    i18n (0.9.1)
+    i18n (0.9.5)
       concurrent-ruby (~> 1.0)
     i18n-js (3.0.0.rc14)
       i18n (~> 0.6, >= 0.6.6)
@@ -274,7 +274,7 @@ GEM
     mime-types-data (3.2016.0521)
     mini_mime (1.0.0)
     mini_portile2 (2.3.0)
-    minitest (5.10.3)
+    minitest (5.11.3)
     moneta (0.8.1)
     multi_json (1.12.1)
     multi_xml (0.5.5)
@@ -288,10 +288,10 @@ GEM
     parser (2.4.0.2)
       ast (~> 2.3)
     pg (0.19.0)
-    pg_search (1.0.6)
-      activerecord (>= 3.1)
-      activesupport (>= 3.1)
-      arel
+    pg_search (2.1.2)
+      activerecord (>= 4.2)
+      activesupport (>= 4.2)
+      arel (>= 6)
     platform-api (2.1.0)
       heroics (~> 0.0.23)
       moneta (~> 0.8.1)
@@ -464,7 +464,7 @@ GEM
     tilt (2.0.5)
     timecop (0.8.1)
     transitions (0.1.13)
-    tzinfo (1.2.4)
+    tzinfo (1.2.5)
       thread_safe (~> 0.1)
     uglifier (3.0.2)
       execjs (>= 0.3.0, < 3)