Prepare reproducible build.

.github/workflows/on_pull_request_build_contracts.yml

@@ -0,0 +1,14 @@
+name: On pull request, build contracts
+
+on:
+  pull_request:
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    uses: multiversx/mx-sc-actions/.github/workflows/[email protected]
+    with:
+      image_tag: v4.2.1
+      package_whole_project_src: true

.gitignore

@@ -2,9 +2,6 @@
 # will have compiled files and executables
 **/target/
 **/output/
-# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
-# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
-Cargo.lock
 
 # These are backup files generated by rustfmt
 **/*.rs.bk