Update net-http requirement from ~> 0.6.0 to >= 0.6, < 0.8

Updates the requirements on [net-http](https://github.com/ruby/net-http) to permit the latest version.
- [Release notes](https://github.com/ruby/net-http/releases)
- [Commits](ruby/net-http@v0.6.0...v0.7.0)

---
updated-dependencies:
- dependency-name: net-http
  dependency-version: 0.7.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

linzer.gemspec

@@ -36,6 +36,6 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency "stringio", "~> 3.1", ">= 3.1.2"
   spec.add_runtime_dependency "logger", "~> 1.7", ">= 1.7.0"
   spec.add_runtime_dependency "forwardable", "~> 1.3", ">= 1.3.3"
-  spec.add_runtime_dependency "net-http", "~> 0.6.0"
+  spec.add_runtime_dependency "net-http", ">= 0.6", "< 0.8"
   spec.add_runtime_dependency "cgi", ">= 0.4.2", "< 0.6.0"
 end