7.8.0 Release

[jmlrt]

This PR prepare 7.8 branch for 7.8.0 release:

• bump chart and Docker images version from 7.8.0-SNAPSHOT to 7.8.0
• remove notices on README that this is a development branch and development branch specific install instructions

Note

• remove notices on README that this is a development branch and development branch specific install instructions

This is required because released Helm charts will be packaged from this PR commit including the README files that will be available inside the chart packages and in Helm Hub pages (example: Elasticsearch chart page).

This change will be reverted in the next PR after release when we will bump 7.8 branch to 7.8.1-SNAPSHOT version.

Replace #672

[Conky5]

LGTM

[jmlrt]

7.8.0 Release changes (to add to GitHub release and changelog):

7.8.0 - 2020/06/18

• 7.8.0 as the default stack version
• Helm 2.16.9 support in #667 @jmlrt

APM Server

PR	Author	Title
#664	@jmlrt	Increase memory limit
#671	@jmlrt	Allow customizing probes

Elasticsearch

PR	Author	Title
#437	desaintmartin	Remove heritage from selector
#542	@floretan	Disable service links to prevent very long startup times
#671	@jmlrt	Update kind example for version >= 0.7.0

Logstash

PR	Author	Title
#392	@jmlrt	Add security example

[jmlrt]

elastic+helm-charts+pull-request+integration-logstash/287/KUBERNETES_VERSION=1.15,LOGSTASH_SUITE=default is a transient error not related to this PR.

The other tests are OK