Upgrade to Pex 2.1.33. (pantsbuild#11647)

This pulls in a fix for handling the et-xmlfile distribution
that was affecting a user.

[ci skip-rust]

[ci skip-build-wheels]

3rdparty/python/constraints.txt

@@ -1,4 +1,4 @@
-# Generated by build-support/bin/generate_lockfile.sh on Thu Feb 25 03:23:18 PM PST 2021
+# Generated by build-support/bin/generate_lockfile.sh on Mon Mar  8 08:12:24 AM PST 2021
 ansicolors==1.1.8
 attrs==20.3.0
 beautifulsoup4==4.6.3
@@ -14,7 +14,7 @@ monotonic==1.5
 mypy==0.800
 mypy-extensions==0.4.3
 packaging==20.9
-pex==2.1.32
+pex==2.1.33
 pip==20.2.3
 pluggy==0.13.1
 psutil==5.7.0

3rdparty/python/requirements.txt

@@ -15,7 +15,7 @@ mypy==0.800
 
 packaging==20.9
 pathspec==0.8.0
-pex==2.1.32
+pex==2.1.33
 psutil==5.7.0
 pystache==0.5.4
 # This should be kept in sync with `pytest.py`.

src/python/pants/backend/python/util_rules/pex_cli.py

@@ -37,7 +37,7 @@ class PexBinary(TemplatedExternalTool):
     name = "pex"
     help = "The PEX (Python EXecutable) tool (https://github.com/pantsbuild/pex)."
 
-    default_version = "v2.1.32"
+    default_version = "v2.1.33"
     default_url_template = "https://github.com/pantsbuild/pex/releases/download/{version}/pex"
 
     @classproperty
@@ -47,8 +47,8 @@ def default_known_versions(cls):
                 (
                     cls.default_version,
                     plat,
-                    "9cea86ae4338943ab347a5e2b3a71e3c27b9835cdd5c115c52d1a328fdb61160",
-                    "3071734",
+                    "7f9f6168691fe83f38fbc248bd8629a152cf2a8833be1afdc06219f70fbb6064",
+                    "3596348",
                 )
             )
             for plat in ["darwin", "linux"]