New changelog scripts (#4491)

* Add templates

* Add folder for local storage of the digests

* Add first draft of the changelog scripts

* Enable Audits in the change template

* Fixes for Polkadot

* Fix templating issue in case there is no high prio change

* Fix Ruby setup

* Remove shell

* Fix chain names

* Fix ENV

* Fix how to get runtime

* Fix runtime_dir

* Fix context location

* Pin changelogerator to a specific version

polkadot/scripts/changelog/templates/changes_runtime.md.tera

@@ -0,0 +1,19 @@
+{%- import "change.md.tera" as m_c -%}
+
+### Runtime
+
+{#- The changes are sorted by merge date -#}
+{% for pr in changes | sort(attribute="merged_at") -%}
+
+{%- if pr.meta.B -%}
+{%- if pr.meta.B.value == 0 -%}
+{#- We skip silent ones -#}
+{%- else -%}
+
+{%- if pr.meta.B.value == 7 and not pr.title is containing("ompanion") %}
+- {{ m_c::change(c=pr) }}
+{%- endif -%}
+{%- endif -%}
+
+{%- endif -%}
+{%- endfor %}