Update examples, set schema on context with each request

[peggyrayzis]

• Added a remote-todo-schema example which is the same as todo, except it adds a merged remote schema
• Upgraded all examples versions

[codecov-io]

Codecov Report

Merging #197 into master will decrease coverage by 0.04%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #197      +/-   ##
=========================================
- Coverage   96.15%   96.1%   -0.05%     
=========================================
  Files           2       2              
  Lines          78      77       -1     
  Branches       21      22       +1     
=========================================
- Hits           75      74       -1     
  Misses          3       3

Impacted Files	Coverage Δ
packages/apollo-link-state/src/index.ts	96.87% <100%> (-0.05%)	⬇️

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