README.md: Fix info about building

"go get" is deprecated. Use "go install" instead.

Signed-off-by: Vinicius Aquino <vinicius.aquino@ossystems.com.br>

README.md

@@ -84,24 +84,23 @@ bundling static assets inside of Go binaries use by
 To install Packr utility and the dependencies:
 
 ```
-$ go get -u github.com/gobuffalo/packr/packr
-$ go get -u github.com/gobuffalo/packr
+$ go install github.com/gobuffalo/packr/v2/packr2@latest
 ```
 
 
 Finally, you can build `updatehub-ce` as:
 
 ```
 $ cd <YOUR-UPDATEHUB-CE-PATH>/ui/ && yarn install && yarn run build && cd ..
-$ packr install
+$ ~/go/bin/packr2 install
 $ go build
 $ go install
 ```
 
 Now you can run the `updatehub-ce` as:
 
 ```
-./updatehub-ce --http 8080
+~/go/bin/updatehub-ce --http 8080
 ```
 
 ## Yocto Project