update rfc to follow changes

docs/rfc/003-imports-stabilization.md

@@ -25,9 +25,7 @@ that we suggest few changes to Leo CLI and Manifest:
 - allow custom names for imports to manually resolve name conflicts;
 - add "curve" and "proving system" sections to the Manifest;
 - add "include" and "exclude" parameters for "proving system" and "curve";
-
-Later this solution can be improved by adding a lock-file which would lock
-imported packages based on both their contents and version. 
+- add a lock file which would store imported dependencies and their relations;
 
 # Motivation
 
@@ -109,12 +107,7 @@ To support updated Manifest new command should be added to Leo CLI.
 
 ```bash
 # pull imports
-leo install
-```
-
-Alternatively it can be called `pull`.
-```
-leo pull
+leo fetch
 ```
 
 ## Imports Restructurization
@@ -155,6 +148,44 @@ first-program  => author1-program@0.1.0
 second-program => author2-program2@1.0.4
 ```
 
+## Leo.lock
+
+For imports map to be generated and read by the Leo binary and then by the Leo compiler,
+lock file needs to be created. Lock file should be generated by the `leo fetch` command
+which will pull the dependencies, process their manifests and put the required information
+to the file in the root directory of the program called `Leo.lock`.
+
+Suggested structure of this file is similar to the Cargo.lock file:
+
+```
+[[package]]
+name = "suit-mk2"
+version = "0.2.0"
+author = "ironman"
+import_name = "suit-mk2"
+
+[package.dependencies]
+garbage = "ironman-suit@0.1.0"
+
+[[package]]
+name = "suit"
+version = "0.1.0"
+author = "ironman"
+import_name = "garbage"
+```
+
+In the example above you can see that all program dependencies are defined as an
+array called `package`, and each of the dependencies contains main information about
+it, including the `import_name` field which is the name of the imported package in
+the Leo program. Also, it stores relationships between these dependencies in the
+field `dependencies`.
+
+Format described here allows the Leo binary to form an imports map which can be
+passed to the compiler.
+
+It is important to note that Leo.lock file is created only when package has dependencies.
+For programs with no dependencies lock file is not required and not created. 
+
 ## Recursive Dependencies
 
 This improvement introduces recursive dependencies. To solve this case preemptively