tools: Avoid subprocess.run(capture_output) argument for Python <3.7 compatibility

In Python 3.5 and 3.6 the equivalent to capture_output=True is to set stdout
and stderr arguments to subprocess.PIPE

tools/ci/deploy_docs.py

@@ -204,9 +204,9 @@ def is_stable_version(version):
     if "-" in version:
         return False  # prerelease tag
 
-    git_out = subprocess.run(["git", "tag", "-l"], capture_output=True, check=True)
+    git_out = subprocess.check_output(["git", "tag", "-l"]).decode("utf-8")
 
-    versions = [v.strip() for v in git_out.stdout.decode("utf-8").split("\n")]
+    versions = [v.strip() for v in git_out.split("\n")]
     versions = [v for v in versions if re.match(r"^v[\d\.]+$", v)]  # include vX.Y.Z only
 
     versions = [packaging.version.parse(v) for v in versions]

tools/idf_tools.py

@@ -224,7 +224,7 @@ def run_cmd_check_output(cmd, input_text=None, extra_paths=None):
     try:
         if input_text:
             input_text = input_text.encode()
-        result = subprocess.run(cmd, capture_output=True, check=True, input=input_text)
+        result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, check=True, input=input_text)
         return result.stdout + result.stderr
     except (AttributeError, TypeError):
         p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)