"spare_wen0" pin missing in the output lib file

[zpzhu99]

Describe the bug
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For single port sram generated, the pin "spare_wen0" is missing in the lib file.

Version
Which commit are you using?
Both Version 1.2.1 and 1.2.6 have this issue.

To Reproduce
What did you do to demonstrate the bug?
Please include your configuration file used.

word_size = 8 # Bits
num_words = 1024
human_byte_size = "{:.0f}kbytes".format((word_size * num_words)/1024/8)

# Allow byte writes
write_size = 8 # Bits

# Single port
num_rw_ports = 1
num_r_ports = 0
num_w_ports = 0
num_spare_rows = 1
num_spare_cols = 1
ports_human = '1rw'
esp_name = "esp_aux_single"

import os
exec(open(os.path.join(os.path.dirname(__file__), 'sky130_sram_common.py')).read())

tech_name = "sky130"
nominal_corner_only = True

# Local wordlines have issues with met3 power routing for now
#local_array_size = 16

route_supplies = "ring"
#route_supplies = "left"
check_lvsdrc = False
uniquify = True
#perimeter_pins = False
#netlist_only = True
#analytical_delay = False

num_threads = 4

output_name = "{tech_name}_{esp_name}_sram_{human_byte_size}_{ports_human}_{word_size}x{num_words}_{write_size}".format(**locals())
output_path = "macro/{output_name}".format(**locals())

Expected behavior
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Logs
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Additional context
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