fix rspec deprecated warning

[hkobayash]

fix below deprecated warnings.

The implicit block expectation syntax is deprecated, you should pass a block rather than an argument to `expect` to use the provided block expectation matcher or the matcher must implement `supports_value_expectations?`. e.g  `expect { value }.to raise BacklogKit::Error with "ConnectionError - getaddrinfo: nodename nor servname provided, or not known"` not `expect(value).to raise BacklogKit::Error with "ConnectionError - getaddrinfo: nodename nor servname provided, or not known"`

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (075f812) to head (a2b2993).

Additional details and impacted files

@@            Coverage Diff            @@
##              main        #5   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           25        25           
  Lines          568       568           
=========================================
  Hits           568       568           

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