build: fix Sourcemap for "/*.mjs" points to missing source files

Signed-off-by: Lexus Drumgold <[email protected]>

Author: unicornware

package.json

@@ -26,7 +26,8 @@
   },
   "type": "module",
   "files": [
-    "dist"
+    "dist",
+    "src"
   ],
   "exports": {
     ".": "./dist/index.mjs",

src/.npmignore

@@ -0,0 +1,8 @@
+# NPM IGNORE
+# https://npm.github.io/publishing-pkgs-docs/publishing/the-npmignore-file.html
+# https://github.com/yarnpkg/yarn/issues/685#issuecomment-457618561
+
+# DIRECTORIES & FILES
+**/__mocks__/**
+**/__snapshots__/**
+**/__tests__/**