Update changelog for 3.1.0

CHANGELOG.rst

@@ -1,3 +1,12 @@
+3.1.0 - August 19, 2022 (sha 28067e22377a60423e7fcf4f995ce224307b8b09)
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+
+* Added app credentials support to openstack.
+* Added VM instance create time property to all providers (thanks to @rodrigonull)
+* Added Azure stop VM instance method (thanks to @rodrigonull)
+* Cloud provider sdks updated to latest versions
+* Other misc fixes.
+
 3.0.0 - December 3, 2021 (sha 327e330bed78b8b70c9ff9d256513d71bc27545f)
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@@ -6,7 +15,7 @@
   instead of `pip install cloudbridge` to obtain previous behaviour. This is to allow greater control over what
   providers are installed. To install only specific providers, use `pip install cloudbridge[aws,gcp]` etc. #292
   (thanks to @RyanSiu1995)
-* Allow users to create signed urls with write permissions #292 (thanks to @FabioRosado)
+* Allow users to create signed urls with write permissions #294 (thanks to @FabioRosado)
 
 2.2.0 - November 5, 2021 (sha f3fb8e18781cd3ede4509ef75a69e7c2a420a167)
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