Add Showruler to Sheetview

[JDavidVR]

This adds showRuler="false" to hide ruler from sheetView

<sheetViews>
<sheetView workbookViewId="0" zoomScaleNormal="100" view="pageLayout" showRuler="false" tabSelected="1" showRowColHeaders="0" showGridLines="0"/>
</sheetViews>

[codecov-commenter]

Codecov Report

Merging #1138 (319a5da) into master (862dc9d) will decrease coverage by 0.01%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master    #1138      +/-   ##
==========================================
- Coverage   98.21%   98.20%   -0.02%     
==========================================
  Files          29       29              
  Lines       18626    18630       +4     
==========================================
+ Hits        18294    18296       +2     
- Misses        226      228       +2     
  Partials      106      106              

Flag	Coverage Δ
unittests	98.20% <50.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
sheetview.go	94.66% <50.00%> (-2.52%)	⬇️

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[xuri]

Thanks for your PR. I've left a comment.

[xuri]

LGTM, thank you very much.