Add appender_telegram

[artemklevtsov]

Hi,

I added appender_telegram by analogy with appender_slack based on the telegram package.

[codecov-io]

Codecov Report

Merging #14 into master will decrease coverage by 2.58%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master      #14      +/-   ##
==========================================
- Coverage   85.01%   82.43%   -2.59%     
==========================================
  Files          10       10              
  Lines         287      296       +9     
==========================================
  Hits          244      244              
- Misses         43       52       +9

Impacted Files	Coverage Δ
R/appenders.R	28.57% <0%> (-9.9%)	⬇️

---

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 ad84388...7e6397e. Read the comment docs.

[codecov-io]

Codecov Report

Merging #14 into master will decrease coverage by 2.58%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master      #14      +/-   ##
==========================================
- Coverage   85.01%   82.43%   -2.59%     
==========================================
  Files          10       10              
  Lines         287      296       +9     
==========================================
  Hits          244      244              
- Misses         43       52       +9

Impacted Files	Coverage Δ
R/appenders.R	28.57% <0%> (-9.9%)	⬇️

---

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 ad84388...2fc7324. Read the comment docs.

[daroczig]

Awesome, thanks! Can you pls run roxygen before merge?

[artemklevtsov]

Done,

[daroczig]

Thank you!