add `.npmignore` files to ignore .gitignore when packing (#3380)

See: https://www.npmjs.com/package/npm-packlist
Fixes: https://github.com/transloadit/uppy/issues/3360
Fixes: https://github.com/transloadit/uppy/issues/3378

packages/@uppy/angular/.npmignore

@@ -0,0 +1 @@
+# This file need to be there so .gitignored files are still uploaded to the npm registry.

packages/@uppy/companion/.npmignore

@@ -0,0 +1 @@
+# This file need to be there so .gitignored files are still uploaded to the npm registry.

packages/@uppy/svelte/.npmignore

@@ -0,0 +1 @@
+# This file need to be there so .gitignored files are still uploaded to the npm registry.

packages/@uppy/vue/.npmignore

@@ -0,0 +1 @@
+# This file need to be there so .gitignored files are still uploaded to the npm registry.

packages/uppy/.npmignore

@@ -0,0 +1 @@
+# This file need to be there so .gitignored files are still uploaded to the npm registry.