ci: force rebuilds on LTS images

Signed-off-by: Chris Kay <chris.kay@arm.com>
Change-Id: Ife6aa132f1150376adb6dce93b06bcf4393f4a23
diff --git a/jammy-amd64-tf-a-build-lts2.10/dummy b/jammy-amd64-tf-a-build-lts2.10/dummy
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/jammy-amd64-tf-a-build-lts2.10/dummy
diff --git a/jammy-amd64-tf-a-build-lts2.12/dummy b/jammy-amd64-tf-a-build-lts2.12/dummy
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/jammy-amd64-tf-a-build-lts2.12/dummy
diff --git a/jammy-amd64-tf-a-build-lts2.8/dummy b/jammy-amd64-tf-a-build-lts2.8/dummy
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/jammy-amd64-tf-a-build-lts2.8/dummy