scripts: west_commands: patch: treat all subprocess output as text

Pass 'encoding="utf-8"' to all 'subprocess.run()' calls.
This treats the captured stdout and stderr streams as text rather than
byte sequences.

Example without this patch:
west patch apply --roll-back
ERROR: b'error: patch failed: examples/csp_server_client.py:32\n
error: examples/csp_server_client.py: patch does not apply\n'
FATAL ERROR: failed to apply patch libcsp/test.patch

Example with this patch:
west patch apply --roll-back
ERROR: error: patch failed: examples/csp_server_client.py:32
error: examples/csp_server_client.py: patch does not apply

FATAL ERROR: failed to apply patch libcsp/test.patch

Signed-off-by: Mirai SHINJO <oss@mshinjo.com>

Author: mshinjo

scripts/west_commands/patch.py

@@ -391,7 +391,9 @@ def apply(self, args, yml, dst_mods=None):
             self.dbg(f"patching {mod}... ", end="")
             apply_cmd += patch_path
             apply_cmd_list.extend([patch_path])
-            proc = subprocess.run(apply_cmd_list, capture_output=True, cwd=mod_path)
+            proc = subprocess.run(
+                apply_cmd_list, capture_output=True, cwd=mod_path, encoding="utf-8"
+            )
             if proc.returncode:
                 self.dbg("FAIL")
                 self.err(proc.stderr)
@@ -430,7 +432,9 @@ def clean(self, args, yml, dst_mods=None):
             try:
                 if checkout_cmd:
                     self.dbg(f"Running '{checkout_cmd}' in {mod}.. ", end="")
-                    proc = subprocess.run(checkout_cmd_list, capture_output=True, cwd=mod_path)
+                    proc = subprocess.run(
+                        checkout_cmd_list, capture_output=True, cwd=mod_path, encoding="utf-8"
+                    )
                     if proc.returncode:
                         self.dbg("FAIL")
                         self.err(f"{checkout_cmd} failed for {mod}\n{proc.stderr}")
@@ -439,7 +443,9 @@ def clean(self, args, yml, dst_mods=None):
 
                 if clean_cmd:
                     self.dbg(f"Running '{clean_cmd}' in {mod}.. ", end="")
-                    proc = subprocess.run(clean_cmd_list, capture_output=True, cwd=mod_path)
+                    proc = subprocess.run(
+                        clean_cmd_list, capture_output=True, cwd=mod_path, encoding="utf-8"
+                    )
                     if proc.returncode:
                         self.dbg("FAIL")
                         self.err(f"{clean_cmd} failed for {mod}\n{proc.stderr}")