fix:web: declare embedded file, fix compilation failure [#2397]

Author: simonmichael

hledger-web/hledger-web.cabal

@@ -34,6 +34,7 @@ extra-source-files:
     README.md
     config/favicon.ico
     config/keter.yaml
+    config/openapi.yaml
     config/robots.txt
     config/routes
     config/settings.yml

hledger-web/package.yaml

@@ -28,6 +28,7 @@ extra-source-files:
 - README.md
 - config/favicon.ico
 - config/keter.yaml
+- config/openapi.yaml
 - config/robots.txt
 - config/routes
 - config/settings.yml