[DEVOPS-61]  repair Appveyor caching (#1782)
[DEVOPS-61]  repair Appveyor caching (#1782)

* Change dir to workdir in CI so stack's cache can be retained

* [DEVOPS-61]  Document the fix

* [DEVOPS-61]  Bump version from 0.4 to 1.0

* [DEVOPS-61]  Verify that the stack cache is populated and fail the build otherwise

* [DEVOPS-61]  Compute VERSION from APPVEYOR_BUILD_VERSION

input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/cardano-sl