Double quotes break in commits JSON parsing

Double quotes in the body of a commit cause parsing failures in the Ruby pre-receive hook script file.

pre-receive hook declined
/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/json-2.3.0/lib/json/common.rb:156:in `parse': 783: unexpected token at '{"author": {"name":"Stefano Puri","mail":"stefano.puri@intecs.it"},"committer":{"name":"Stefano Puri","mail":"stefano.puri@intecs.it"},"body":"Revert "initial extensions to support CONCERTO-FLA"  This reverts commit 0a1be2bfe130b98b9573e42359c5597bd4c9d77b. ","subject":"Revert "initial extensions to support CONCERTO-FLA"","hash":"bd302ecc574e29b7cfd64843c3c0c6bf19ea7944", "parents":["1ce0635ece0d3394204e9c5198487995e97e52bf"]} ' (MultiJson::ParseError)
	from /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/json-2.3.0/lib/json/common.rb:156:in `parse'
	from /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/multi_json-1.14.1/lib/multi_json/adapters/json_common.rb:14:in `load'
	from /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/multi_json-1.14.1/lib/multi_json/adapter.rb:21:in `load'
	from /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/multi_json-1.14.1/lib/multi_json.rb:122:in `load'
	from /opt/gitlab/embedded/service/gitlab-shell/hooks/pre-receive.d/eca.rb:52:in `block in <main>'
	from /opt/gitlab/embedded/service/gitlab-shell/hooks/pre-receive.d/eca.rb:44:in `each'
	from /opt/gitlab/embedded/service/gitlab-shell/hooks/pre-receive.d/eca.rb:44:in `<main>'