Update installation instructions to account for the registration of r…

…elease 0.3.0

README.md

@@ -24,15 +24,21 @@ Linux and MacOS.
 
 ## Installation
 
-From Julia REPL, type `]` to enter in the package manager and type
+To install the latest release, type from the Julia REPL, type `]` to enter in the package manager and then,
 
 ```
-add https://github.com/JuliaHEP/ROOT.jl
+add ROOT
 ```
 
-Registration in the General repository is in progress. Once it will be done, `add ROOT` will be used.
+The developement version (github HEAD) can be installed using,
+
+```
+dev https://github.com/JuliaHEP/ROOT.jl
+build ROOT
+```
+
+⚠ Installation can stay several minutes (ten of minutes on macOS) on the following message.
 
-⚠️  Installation can stay several minutes (ten of minutes on macOS) on the following message.
 
 ```
 Building ROOT → `.../build.log`
@@ -41,6 +47,8 @@ Building ROOT → `.../build.log`
 
 This is due to the installation of ROOT and compilation of the wrapper library. **Be patient**. You can open the indicated `build.log` file to see the progress.
 
+💡 Sometimes the `build.jl` script is not launched by the package manager. It is for instance the case in the development mode (package added with the `dev` command). In case of the command `add ...` command fail, try first to run `build ROOT` from the package manager prompt before investigating further.
+
 ## ROOT version
 
 Current ROOT version uses ROOT release 6.30.04. If a ROOT installation is found in the default binary search paths (PATH environment variable) with this version, then it will be used. Otherwise, ROOT will be installed using [Conda](https://github.com/JuliaPy/Conda.jl) into `$HOME/.julia/Conda/3`.