Replace fmt.Sprintf with strconv

[hackerwins]

What this PR does / why we need it:

Replace fmt.Sprintf with strconv.

Before

After

Which issue(s) this PR fixes:

Address #251

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Additional documentation:

Checklist:

• Added relevant tests or not required
• Didn't break anything

[codecov]

Codecov Report

Merging #254 (bc3150f) into main (3a3ee81) will increase coverage by 0.07%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #254      +/-   ##
==========================================
+ Coverage   49.87%   49.95%   +0.07%     
==========================================
  Files          54       54              
  Lines        4417     4422       +5     
==========================================
+ Hits         2203     2209       +6     
+ Misses       1997     1996       -1     
  Partials      217      217              

Impacted Files	Coverage Δ
pkg/document/json/rga_tree_split.go	73.87% <100.00%> (+0.45%)	⬆️
pkg/document/time/ticket.go	100.00% <100.00%> (ø)

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[zeikar]

LGTM 👍