chore: Add notes about promtail being feature complete (#12827)

Signed-off-by: Callum Styan <[email protected]>
Co-authored-by: J Stickler <[email protected]>

Author: cstyan

.github/pull_request_template.md

@@ -10,6 +10,7 @@ Fixes #<issue number>
 - [ ] Documentation added
 - [ ] Tests updated
 - [ ] Title matches the required conventional commits format, see [here](https://www.conventionalcommits.org/en/v1.0.0/)
+  - **Note** that Promtail is considered to be feature complete, and future development for logs collection will be in [Grafana Alloy](https://github.com/grafana/alloy). As such, `feat` PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
 - [ ] Changes that require user attention or interaction to upgrade are documented in `docs/sources/setup/upgrade/_index.md`
 - [ ] For Helm chart changes bump the Helm chart version in `production/helm/loki/Chart.yaml` and update `production/helm/loki/CHANGELOG.md` and `production/helm/loki/README.md`. [Example PR](https://github.com/grafana/loki/commit/d10549e3ece02120974929894ee333d07755d213)
 - [ ] If the change is deprecating or removing a configuration option, update the `deprecated-config.yaml` and `deleted-config.yaml` files respectively in the `tools/deprecated-config-checker` directory. [Example PR](https://github.com/grafana/loki/pull/10840/commits/0d4416a4b03739583349934b96f272fb4f685d15)

CONTRIBUTING.md

@@ -6,6 +6,8 @@ Loki uses GitHub to manage reviews of pull requests:
 - If you plan to do something more involved, discuss your ideas on the relevant GitHub issue.
 - Make sure to follow the prerequisites below before marking your PR as ready for review.
 
+**Note that Promtail is considered to be feature complete, and future development for logs collection will be in [Grafana Alloy](https://github.com/grafana/alloy)**
+
 ## Loki Improvement Documents (LIDs)
 
 Before creating a large pull request to change or add functionality, please create a _Loki Improvement Document (LID)_. We use LIDs to discuss and vet ideas submitted by maintainers or the community in an open and transparent way. As of Jan 2023, we are starting with a lightweight LID process and we may add more structure, inspired by Python's [PEP](https://peps.python.org/pep-0001/) and Kafka's [KIP](https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals) approaches.

README.md

@@ -24,6 +24,8 @@ A Loki-based logging stack consists of 3 components:
 - `loki` is the main server, responsible for storing logs and processing queries.
 - [Grafana](https://github.com/grafana/grafana) for querying and displaying the logs.
 
+**Note that Promtail is considered to be feature complete, and future development for logs collection will be in [Grafana Alloy](https://github.com/grafana/alloy)**
+
 Loki is like Prometheus, but for logs: we prefer a multidimensional label-based approach to indexing, and want a single-binary, easy to operate system with no dependencies.
 Loki differs from Prometheus by focusing on logs instead of metrics, and delivering logs via push, instead of pull.