Unquote default process type commands

[runesoerensen]

This PR simply removes the quotes around process commands from the output produced by bin/release. This is inconsequential for all currently supported uses of the buildpack.

However, the recently adopted CNB changes to support paths with spaces won't work as expected in the following scenario:

• The CNB_EXEC_ENV config var is set to test.
• The solution/project filename includes spaces/special characters.

Which results in bin/release output like this:

---
default_process_types:
  test: "dotnet test "solution with spaces.sln""

This is very much an unsupported use case currently, as launch.toml processes used by bin/release never contains double quotes (when targeting the production execution environment), and the argument quoting introduced by #67 only affects launch.toml parsing used in bin/test.

It's of course still worth fixing as the command quoting in bin/release is unnecessary / not required by neither the Procfile nor the Buildpack API specs. It's also quite likely that the CNB will produce launch.toml processes differently in the future, e.g. to support Development execution environments.