install: revert pre-release instructions change

per #1195 (review)

content/blog/2020-05-04-dvc-3-years-and-1-0-release.md

@@ -92,8 +92,8 @@ All these contributions, big and small, have a collective impact on DVC's
 development. I'm happy (and a bit nervous) to announce that a pre-release of a
 brand new DVC 1.0 is ready for public beta testing.
 
-You can install the pre-release version from the development branch (instruction
-on [our website](https://dvc.org/doc/install/pre-release)) or through pip:
+You can install the 1.0 pre-release from the master branch in our repo
+(instruction [here](https://dvc.org/doc/install/pre-release)) or through pip:
 
 ```dvc
 $ pip install --upgrade --pre dvc

content/docs/install/pre-release.md

@@ -10,9 +10,15 @@ releases, you can install it from our code repository GitHub.
 > (on Python 3.6+) to encapsulate your local environment.
 
 ```dvc
-$ pip install --upgrade --pre dvc
+$ pip install gitpython
+$ pip install git+https://github.com/iterative/dvc
 ```
 
-To install a development version for contributing to the project, please refer
-to
+> `gitpython` allows the installation process to generate a DVC version using
+> the current Git commit hash. This lets us to distinguish official DVC releases
+> (e.g. `0.64.3`) from a development version (e.g. `0.64.3-9c7381`). For more
+> information on our versioning convention, refer to
+> [Components of DVC version](/doc/command-reference/version#components-of-dvc-version).
+
+To install a development version, for contributing to the project, please see
 [Development environment](/doc/user-guide/contributing/core#development-environment).