Changed python versions in install doc (PR #2881)

# Description

Small documentation improvement

# Self Check:

Strike through any lines that are not applicable (`~~line~~`) then check the box

- [ ] Attached issue to pull request
- [ ] Changelog entry
- [ ] Type annotations are present
- [ ] Code is clear and sufficiently documented
- [ ] No (preventable) type errors (check using make mypy or make mypy-diff)
- [ ] Sufficient test cases (reproduces the bug/tests the requested feature)
- [ ] Correct, in line with design
- [ ] End user documentation is included or an issue is created for end-user documentation (add ref to issue here: )

# Reviewer Checklist:

- [ ] Sufficient test cases (reproduces the bug/tests the requested feature)
- [ ] Code is clear and sufficiently documented
- [ ] Correct, in line with design

changelogs/unreleased/update-install-docs.yml

@@ -0,0 +1,6 @@
+---
+description: Changed python versions in install doc
+change-type: patch
+destination-branches: [master, iso4]
+sections:
+  bugfix: "{{description}}"

docs/install/1-install-server.rst

@@ -4,7 +4,7 @@ Install Inmanta
 ***************
 
 This page explains how to install the Inmanta orchestrator software and setup an orchestration server. Regardless what platform
-you installed it on, Inmanta requires at least the latest Python 3.6 or 3.7 and git.
+you installed it on, Inmanta requires at least the latest Python 3.6 and git to be installed.
 
 .. include:: ./install-server/install-server.inc
 .. include:: ./install-server/configure-postgres.inc