chore: grammar error in README is fixed

[AB261]

Fixes #1405

Checklist:

• I have checked for PMD and check-style issues
• I have read the Contribution & Best practices Guide and my PR follows them.
• My branch is up-to-date with the Upstream development branch.

Changes: Under project conventions in the README fixed the grammar error where it said "There is certain conventions" to "There are certain conventions"

[codecov]

Codecov Report

Merging #1406 into development will increase coverage by 0.01%.
The diff coverage is n/a.

@@                Coverage Diff                @@
##             development    #1406      +/-   ##
=================================================
+ Coverage          24.45%   24.46%   +0.01%     
  Complexity           757      757              
=================================================
  Files                237      237              
  Lines               8658     8658              
  Branches             351      351              
=================================================
+ Hits                2117     2118       +1     
+ Misses              6458     6457       -1     
  Partials              83       83

Impacted Files	Coverage Δ	Complexity Δ
...izer/core/ticket/create/CreateTicketViewModel.java	86.27% <0%> (+1.96%)	14% <0%> (ø)	⬇️

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[iamareebjamal]

Please follow semantic Pull Request guidelines and change the PR title with imperative message

[iamareebjamal]

docs: correct grammatical mistake of README would have been better 😄