support new options for template message images

[tw0517tw]

close #246

[codecov]

Codecov Report

Merging #247 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff           @@
##           master    #247   +/-   ##
======================================
  Coverage    97.6%   97.6%           
======================================
  Files          16      16           
  Lines         543     543           
  Branches       52      52           
======================================
  Hits          530     530           
  Misses         13      13

Impacted Files	Coverage Δ
packages/messaging-api-line/src/Line.js	92.3% <ø> (ø)	⬆️
packages/messaging-api-line/src/LineClient.js	97.77% <100%> (ø)	⬆️

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