feat: set rust's toolchain

tasks/install-rust.yml

@@ -16,11 +16,16 @@
     - rust
     - prereq
 
+- name: Set environment variables if not set
+  ansible.builtin.set_fact:
+    cargo_home: "{{ cargo_home | default(xdg_data_home + '/cargo') }}"
+    rustup_home: "{{ rustup_home | default(xdg_data_home + '/rustup') }}"
+
 - name: Install Rust & Cargo
   when: cargo_installed.rc != 0
   environment:
-    CARGO_HOME: "{{ cargo_home | default(xdg_data_home + '/cargo') }}"
-    RUSTUP_HOME: "{{ rustup_home | default(xdg_data_home + '/rustup') }}"
+    CARGO_HOME: "{{ cargo_home }}"
+    RUSTUP_HOME: "{{ rustup_home }}"
   ansible.builtin.command:
     argv:
       - /tmp/sh.rustup.rs
@@ -29,3 +34,14 @@
   tags:
     - rust
     - prereq
+
+- name: Set Rustup's toolchain
+  ansible.builtin.command:
+    argv:
+      - rustup
+      - default
+      - "{{ rustup_toolchain | default('stable') }}"
+  environment:
+    CARGO_HOME: "{{ cargo_home }}"
+    RUSTUP_HOME: "{{ rustup_home }}"
+  changed_when: true