chore: update mind_paystack version in multiple applications

- Updated mind_paystack to version 0.1.2 in ex00_checkout_basic and ex02_charge_terminal.
- Updated mind_paystack to version 0.1.2+1 in ex01_checkout_flutter and ex05_plan_demo.

Author: Yczar

apps/ex00_checkout_basic/pubspec.lock

@@ -263,7 +263,7 @@ packages:
       path: "../../packages/mind_paystack"
       relative: true
     source: path
-    version: "0.1.1+1"
+    version: "0.1.2"
   mocktail:
     dependency: "direct main"
     description:

apps/ex01_checkout_flutter/pubspec.lock

@@ -238,7 +238,7 @@ packages:
       path: "../../packages/mind_paystack"
       relative: true
     source: path
-    version: "0.1.1+1"
+    version: "0.1.2+1"
   path:
     dependency: transitive
     description:

apps/ex02_charge_terminal/pubspec.lock

@@ -263,7 +263,7 @@ packages:
       path: "../../packages/mind_paystack"
       relative: true
     source: path
-    version: "0.1.1+1"
+    version: "0.1.2"
   node_preamble:
     dependency: transitive
     description:

apps/ex05_plan_demo/pubspec.lock

@@ -255,7 +255,7 @@ packages:
       path: "../../packages/mind_paystack"
       relative: true
     source: path
-    version: "0.1.1+1"
+    version: "0.1.2+1"
   node_preamble:
     dependency: transitive
     description: