rpm/deb/osxpkg: add url and license (#4098)

We are currently missing url and license metadata:
```
Name        : dvc
Arch        : x86_64
Version     : 0.94.0
Release     : 1
Size        : 172 M
Repo        : installed
From repo   : dvc
Summary     : Data Version Control - datasets, models, and experiments
versioning for ML or data science projects
URL         : http://example.com/no-uri-given
License     : unknown
Description : Data Version Control - datasets, models, and experiments
versioning for ML or data science projects
```

https://github.com/iterative/dvc/issues/4088#issuecomment-648270797

scripts/build_posix.sh

@@ -53,6 +53,8 @@ fpm_build() {
     -f \
     -t $1 \
     --description "$DESC" \
+    --url https://dvc.org \
+    --license "Apache License 2.0" \
     $FPM_FLAGS \
     -n dvc \
     -v $VERSION \