Remove sys-proctable dependency, only needed on Windows.

Index: .metadata
--- .metadata.orig
+++ .metadata
@@ -51,9 +51,6 @@ dependencies:
     - - ">="
       - !ruby/object:Gem::Version
         version: 1.11.4
-    - - "<"
-      - !ruby/object:Gem::Version
-        version: 1.14.0
   type: :runtime
   prerelease: false
   version_requirements: !ruby/object:Gem::Requirement
@@ -167,7 +164,7 @@ dependencies:
     - - "~>"
       - !ruby/object:Gem::Version
         version: 1.2.2
-  type: :runtime
+  type: :development
   prerelease: false
   version_requirements: !ruby/object:Gem::Requirement
     requirements: