requirements.txt: tighten ranges

diff --git a/requirements.txt b/requirements.txt
index adc8a4869f04faffbe8d586c3eb27d7db1689dfe..45685c1150d796c27145bcbcc86eeb512ad2f20f 100644 (file)
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,3 @@
-lxml>=4.2.4
-beautifulsoup4>=4.6.1
-flake8>=3.8.3
+lxml>=4.2.4,<=5.0
+beautifulsoup4>=4.6.1,<=5.0
+flake8>=3.8,<=4.0