Add_requirements.txt

testgres can be installed with
pip install -r pg_probackup/tests/requirements.txt

Author: Oleg Gurev

Diff for: tests/requirements.txt

@@ -0,0 +1,13 @@
+# Testgres can be installed in the following ways:
+# 1. From a pip package (recommended)
+#    testgres==1.8.5
+# 2. From a specific Git branch, tag or commit
+#    git+https://github.com/postgrespro/testgres.git@<git-ref>
+# 3. From a local directory
+#    /path/to/local/directory/testgres
+git+https://github.com/postgrespro/testgres.git@master#egg=testgres-pg_probackup2&subdirectory=testgres/plugins/pg_probackup2
+allure-pytest
+deprecation
+pexpect
+pytest
+pytest-xdist