SC-85410 | V2 demos build on schedule (#1358)

## Summary:
Workflows added to build the `master` and `dev` branch on a bi-daily
basis (every two days).

Please note, we will need to check out the `dev` version of the workflow
once this change is merged to `dev`

As seen here:
[from `./workflows/v2-build-demos.yml` ->
`./workflows/v2-build-demos.yml@dev`](https://github.com/PennyLaneAI/qml/pull/1358/files#diff-a7089c8b0db3e46f54708ff72c7fb0c2579efcc28c0a9f5d5ec0071ca99df091R135)

---------

Co-authored-by: Jack Brown <[email protected]>
Co-authored-by: Jack Brown <[email protected]>
Co-authored-by: anthayes92 <[email protected]>
Co-authored-by: Paul Finlay <[email protected]>
Co-authored-by: doctorperceptron <[email protected]>

Author: 4 people

.github/workflows/v2-build-branch-dev.yml

@@ -0,0 +1,21 @@
+name: V2 Build QML Branch - Dev
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 0 * * 0,2,4,6' # At 00:00 on Sunday, Tuesday, Thursday, and Saturday.
+
+concurrency:
+  group: build-qml-demo-branch-dev
+  cancel-in-progress: true
+
+jobs:
+  build_dev:
+    uses: ./.github/workflows/v2-build-demos.yml
+    with:
+      ref: dev
+      dev: true
+      save-artifact: true
+      artifact-name: build-branch-dev
+      keep-going: false
+      quiet: false
+      batch_size: 10

.github/workflows/v2-build-branch-master.yml

@@ -0,0 +1,21 @@
+name: V2 Build QML Branch - Master
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 0 * * 0,2,4,6' # At 00:00 on Sunday, Tuesday, Thursday, and Saturday.
+
+concurrency:
+  group: build-qml-demo-branch-master
+  cancel-in-progress: true
+
+jobs:
+  build_master:
+    uses: ./.github/workflows/v2-build-demos.yml
+    with:
+      ref: master
+      dev: false
+      save-artifact: true
+      artifact-name: build-branch-master
+      keep-going: false
+      quiet: false
+      batch_size: 10