Pin MSRV to 1.41

[sagebind]

1.41 is the version on Debian stable (a common distribution channel) and supports basically everything that we require. Only a few small changes were required to get it to compile with this version.

Fixes #219.

[codecov]

Codecov Report

Merging #259 (6345459) into master (6c97805) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #259      +/-   ##
==========================================
- Coverage   72.14%   72.11%   -0.04%     
==========================================
  Files          49       49              
  Lines        2456     2460       +4     
==========================================
+ Hits         1772     1774       +2     
- Misses        684      686       +2     

Impacted Files	Coverage Δ
src/client.rs	69.69% <100.00%> (-0.81%)	⬇️
src/config/dial.rs	68.62% <100.00%> (+1.31%)	⬆️
src/cookies/cookie.rs	86.40% <100.00%> (+0.22%)	⬆️
tests/redirects.rs	99.02% <100.00%> (ø)
tests/timeouts.rs	100.00% <100.00%> (ø)

---

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 6c97805...6345459. Read the comment docs.