Update README.md

[eaglebush]

Updatred readme.md on parameter type usage

[codecov[bot]]

Codecov Report

Merging #740 (8af75e6) into master (e538731) will decrease coverage by 0.09%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #740      +/-   ##
==========================================
- Coverage   71.29%   71.20%   -0.10%     
==========================================
  Files          24       24              
  Lines        5386     5386              
==========================================
- Hits         3840     3835       -5     
- Misses       1301     1304       +3     
- Partials      245      247       +2     

Impacted Files	Coverage Δ
tds.go	65.13% <0.00%> (-0.73%)	:arrow_down:
token.go	64.35% <0.00%> (+0.14%)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update e538731...8af75e6. Read the comment docs.

[shueybubbles]

We invite you to open this pr to our Microsoft fork at github.com/microsoft/go-mssqldb