CMHeartbeatDiscovery- Updated Heartbeat Discovery Schedule

[NEllis280]

Pull Request (PR) description

This PR adds warnings to the CMHeartbeatDiscovery resource warning when the maximum schedule interval has been exceeded and adds handling for test/set when the specified interval is greater than the maximum allowed.

This Pull Request (PR) fixes the following issues

• Fixes #39

Task list

• [x] Added an entry to the change log under the Unreleased section of the file CHANGELOG.md. Entry should say what was changed and how that affects users (if applicable), and reference the issue being resolved (if applicable).
• [ ] Resource documentation added/updated in README.md.
• [ ] Resource parameter descriptions added/updated in README.md, schema.mof and comment-based help.
• [ ] Comment-based help added/updated.
• [x] Localization strings added/updated in all localization files as appropriate.
• [ ] Examples appropriately added/updated.
• [x] Unit tests added/updated. See DSC Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [x] New/changed code adheres to DSC Community Style Guidelines.

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This change is 

[codecov[bot]]

Codecov Report

Merging #72 (b792c3d) into master (fc05d30) will increase coverage by 0%. The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #72   +/-   ##
=====================================
  Coverage      97%    97%           
=====================================
  Files          34     34           
  Lines        3723   3737   +14     
=====================================
+ Hits         3632   3646   +14     
  Misses         91     91           

[NEllis280]

These checks will be done in other resources. The plan is to do a helper resource later when we expand the types of schedules that can be used.