add egison

Checklist:
- [x] Meaningful commit message, eg `add my-cool-package` (please not mention `build-constraints.yml`)
- [x] At least 30 minutes have passed since uploading to Hackage
- [x] On your own machine, in a _new directory_, you have successfully run the following set of commands (replace `$package` with the name of the package that is submitted, and `$version` with the version of the package you want to get into Stackage):

      stack unpack $package-$version  # $version is optional
      stack init --resolver nightly
      stack build --resolver nightly --haddock --test --bench --no-run-benchmarks

build-constraints.yaml

@@ -4035,6 +4035,9 @@ packages:
     "Davit Nalchevanidze <d.nalchevanidze@gmail.com> @nalchevanidze":
         - morpheus-graphql
 
+    "Satoshi Egi <egi@egison.org> @egisatoshi":
+        - egison
+
     "Grandfathered dependencies":
         - network
         - Boolean