fix: timeout gcm calls

[pjenvey]

Closes #1285

[codecov-io]

Codecov Report

Merging #1286 into master will decrease coverage by 0.03%.
The diff coverage is 57.14%.

@@            Coverage Diff             @@
##           master    #1286      +/-   ##
==========================================
- Coverage     100%   99.96%   -0.04%     
==========================================
  Files          59       59              
  Lines        9566     9571       +5     
==========================================
+ Hits         9566     9568       +2     
- Misses          0        3       +3

Impacted Files	Coverage Δ
autopush/router/gcm.py	97.16% <57.14%> (-2.84%)	⬇️

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