Upgrade Ruby to version 2.7.6

So get the latest fixes in the 2.7.x series.

We're also updating the parser gem so we don't get any warnings.

.gitlab-ci.yml

@@ -3,7 +3,7 @@ stages:
   - lint
 
 tests:
-  image: "ruby:2.7.4"
+  image: "ruby:2.7.6"
   stage: test
   services:
     - postgres:10.10
@@ -34,7 +34,7 @@ tests:
 # PRONTO_GITLAB_API_PRIVATE_TOKEN to your repository CI/CD settings
 # giving it the value of the Personal Access Token
 linters:
-  image: "ruby:2.7.4"
+  image: "ruby:2.7.6"
   stage: lint
   cache:
     key: consul

.ruby-version

@@ -1 +1 @@
-2.7.4
+2.7.6

Dockerfile

@@ -1,4 +1,4 @@
-FROM ruby:2.7.4-buster
+FROM ruby:2.7.6-buster
 
 ENV DEBIAN_FRONTEND noninteractive
 

Gemfile.lock

@@ -430,7 +430,7 @@ GEM
     parallel (1.20.1)
     paranoia (2.4.3)
       activerecord (>= 4.0, < 6.2)
-    parser (3.0.2.0)
+    parser (3.1.2.0)
       ast (~> 2.4.1)
     pg (1.2.3)
     pg_search (2.3.5)

README.md

@@ -38,7 +38,7 @@ You can access the main website of the project at [http://consulproject.org](htt
 
 **NOTE**: For more detailed instructions check the [docs](https://docs.consulproject.org)
 
-Prerequisites: install git, Ruby 2.7.4, CMake, pkg-config, shared-mime-info, Node.js and PostgreSQL (>=9.5).
+Prerequisites: install git, Ruby 2.7.6, CMake, pkg-config, shared-mime-info, Node.js and PostgreSQL (>=9.5).
 
 ```bash
 git clone https://github.com/consul/consul.git

README_ES.md

@@ -36,7 +36,7 @@ Puedes acceder a la página principal del proyecto en [http://consulproject.org]
 
 **NOTA**: para unas instrucciones más detalladas consulta la [documentación](https://docs.consulproject.org)
 
-Prerequisitos: tener instalado git, Ruby 2.7.4, CMake, pkg-config, shared-mime-info, Node.js y PostgreSQL (9.5 o superior).
+Prerequisitos: tener instalado git, Ruby 2.7.6, CMake, pkg-config, shared-mime-info, Node.js y PostgreSQL (9.5 o superior).
 
 ```bash
 git clone https://github.com/consul/consul.git