.github: exclude template branch from workflows
.github: exclude template branch from workflows

Lately I have been using the template branch to track the most recent
commit from the project template repository which has been applied to
(i.e. rebased onto) the project.  I rarely (never?) use it as a topic
branch.  Therefore, exclude it from builds, since there's no sense
building the project template in each project where it is used.

Signed-off-by: Kevin Locke <ffb4761cba839470133bee36aeb139f58d7dbaa9@kevinlocke.name>

kevinoid/promised-read,kevinoid/promised-read,kevinoid/promised-read