VOL-1777 Update python requirements

Set the same across all projects to prevent
build errors.

Also bump SemVer to 0.2.1

Change-Id: I2b67bc06d7ae19e4c8a6e4a3192b784818ecd20b
diff --git a/requirements.txt b/requirements.txt
index c8659a7..0dc586a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -29,7 +29,6 @@
 protobuf-to-dict==0.1.0
 pyflakes==2.1.0
 pylint==1.9.4
-#pypcap>=1.1.5
 pyOpenSSL==17.3.0
 PyYAML==3.12
 requests==2.18.4
@@ -60,4 +59,4 @@
 pexpect==4.6.0
 python-consul==0.6.2
 afkak==3.0.0.dev20181106
-voltha-protos==0.1.4
+voltha-protos>=0.1.4