bash -> sh.

.drone.yml

@@ -7,7 +7,7 @@ steps:
   image: python:3.5-alpine3.9
   pull: always
   commands:
-    - bash scripts/run-tests
+    - sh scripts/run-tests
 ---
 kind: pipeline
 name: python-3-6-alpine-3-9
@@ -17,7 +17,7 @@ steps:
   image: python:3.6-alpine3.9
   pull: always
   commands:
-    - bash scripts/run-tests
+    - sh scripts/run-tests
 ---
 kind: pipeline
 name: python-3-7-alpine-3-9
@@ -27,7 +27,7 @@ steps:
   image: python:3.7-alpine3.9
   pull: always
   commands:
-    - bash scripts/run-tests
+    - sh scripts/run-tests
 ---
 kind: pipeline
 name: python-3-7-alpine-3-7
@@ -37,4 +37,4 @@ steps:
   image: python:3.7-alpine3.7
   pull: always
   commands:
-    - bash scripts/run-tests
+    - sh scripts/run-tests

scripts/run-tests

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 # This script is intended to be run from the continuous integration build
 # server, and not on a developer machine. For that, see: